Timing beats targeting. A perfect-fit company with no budget cycle open will ignore you; an average-fit company that just raised will take the call. Both signals are in the data.
Funding is the loudest signal
A round closes and spending follows within a quarter or two, usually on headcount first and tooling immediately after. Filter on round date rather than total raised: recency matters more than size for outbound timing.
Headcount growth is the quieter one
Companies that grew their team meaningfully in the last six months are actively building something. That is a budget in motion, and it is visible without any funding event at all, which makes it useful for the bootstrapped end of the market.
Funding tells you money arrived. Headcount growth tells you it is already being spent.
Combining the two
Run both filters as separate lists rather than stacking them. Stacked, they cut your count to almost nothing. Side by side, they give you two campaigns with genuinely different openers.
Working the list
Reference the specific signal in the first line. Not "I saw you are growing", but the actual round or the actual role count. That is the difference between a list that reads as researched and one that reads as bought.