Which Buying Lane, Modeling a $15K/Month CTV Budget Across Self-Serve, DSP, and FAST

Marketing Academy · Field Work●Paid Ads

All projects·From: Connected TV & Streaming Ads

MiniForecast· 35 minutes

ThredUp

Objective: Given a fixed monthly CTV budget and a reach/frequency goal, forecast realistic impression volume and blended CPM across the three buying lanes (self-serve, programmatic DSP, FAST channels) to recommend a split.

You're the growth marketer at a ThredUp-style online resale marketplace with a new $15,000/month test budget to move off saturated Meta prospecting and into CTV for the first time.

Model expected impressions and blended CPM for three allocation scenarios, then recommend a split that balances reach against premium-streamer brand lift.

Before you start

What you'll need

Free path (everything below is enough to finish)

Google Sheets

FreeModel impression volume and blended CPM across buying-lane scenarios

No CTV spend required to test the allocation math before committing budget

Paid upgrades (optional, faster/deeper)

Google Ads(optional)

FreeRun the YouTube CTV portion of the blended buy once the allocation is decided

The lesson names YouTube via Google Ads as a real CTV buying lane, and it's the one cataloged tool that actually reaches living-room TV screens

The process

2 steps

Step 01 of 02

Self-serve vs. programmatic DSP vs. FAST channel tradeoffs

The lesson splits CTV buying into three lanes by budget size: self-serve managed platforms ($1K-$250K/month), programmatic DSPs (cross-platform unified buys), and FAST channels ($12-20 CPM vs. $25-65 on premium streamers).

At $15,000/month, is this budget better spent entirely on a premium self-serve platform like Roku Ads Manager, split across FAST channels, or blended?

Google Sheets— Build a 3-row model: Premium-only, FAST-only, and a 60/40 blended scenario.

Procedure

Row 1: $15,000 at a $35 blended premium CPM (Netflix/Hulu range) = ~428,500 impressions
Row 2: $15,000 at a $16 blended FAST CPM (Tubi/Pluto/Roku Channel range) = ~937,500 impressions
Row 3: 60% ($9,000) to FAST at $16 CPM + 40% ($6,000) to premium at $35 CPM = 562,500 + 171,400 = ~733,900 impressions
Compare completion rates: 88-94% on FAST vs. ~95% on premium, both well above social video

Sample output

Scenario          Impressions   Blended CPM   Completion Rate
Premium-only         428,500        $35.00           ~95%
FAST-only             937,500        $16.00         88-94%
60/40 Blend            733,900        $20.44         90-94%

Healthy

The blended scenario delivers 71% more reach than premium-only at a completion rate within a few points of it, using FAST volume to fund a smaller premium presence for brand-safe placements.

Unhealthy

Spending the entire $15,000 on premium streamers because they "sound better," delivering under half the reach for a completion-rate difference of only a few points.

What this means

At this budget size, reach efficiency from FAST channels usually outweighs the marginal completion-rate edge of premium streamers, the lesson's own guidance for advertisers under $20,000/month.

So what do I do about it?

Symptom	Action	Effort
Budget under $20K/month is being allocated 100% to premium streamers	Shift the majority to FAST channels and use premium only for high-value creative moments	30 min

YouYou can do this yourself, no engineering access required.

Step 02 of 02

Unified frequency capping across platforms

The lesson warns that a 3-per-week cap set separately on 3 different DSPs becomes a 9-per-week cap for any household reachable across all three, unless the cap is unified.

The blended plan above runs across 2 self-serve platforms (Roku Ads Manager for FAST, MNTN for premium) with no shared frequency cap set yet. What's the risk and the fix?

Google Sheets— Add a frequency-cap column to the buying-lane model built in step 1.

Procedure

Set a 3-per-week cap inside Roku Ads Manager
Set a separate 3-per-week cap inside MNTN
Recognize any household reachable on both platforms can see up to 6 ads/week instead of the intended 3
Either lower each platform's individual cap to 1-2/week, or move to a single DSP that can enforce one cap across both lanes

Sample output

Household overlap check: 34% of the FAST-reachable audience is also reachable on MNTN's premium inventory -> uncapped combined frequency could hit 6/week for over a third of the target audience.

Healthy

Each platform's cap is set to roughly half the target (1-2/week) to keep the combined ceiling near the intended 3/week for overlapping households.

Unhealthy

Both platforms run their own full 3/week cap independently, quietly doubling frequency for the highest-overlap third of the audience.

What this means

A frequency cap set at the platform level, not the household level, is not really a cap once you're buying across more than one platform.

So what do I do about it?

Symptom	Action	Effort
Two or more CTV platforms are live with the same nominal frequency cap	Halve each platform's individual cap or consolidate into a single DSP that unifies it	30 min

YouYou can do this yourself, no engineering access required.

Final deliverable

A 3-scenario impression/CPM forecast model with a recommended budget split and a frequency-cap plan across platforms.

See a reference example

Sample output

Grab CTV test budget model (excerpt)

Premium-only ($20K):     571,400 impressions at $35 CPM
FAST-only ($20K):      1,250,000 impressions at $16 CPM
Recommended 65/35 blend: 1,043,600 impressions, blended CPM $19.16

Frequency cap: Roku Channel capped at 2/week, premium DSP capped at 1/week, combined ceiling ~3/week for overlapping households.

Success criteria

You're done when you can:

Correctly calculates impression volume from budget divided by CPM for all three scenarios
Identifies the frequency-cap overlap risk and proposes a specific fix