Thanks for your kind words! :)
Population count is a little too transient for that kind of treatment, I think. Consider that in the short term, a slider position that represented "5 builders" would no longer represent 5 builders the moment that an existing bee died or a new bee spawned. Longer term, since going from 0% to 5% Builders for a hypothetical stable population of 100 means a lower allocation of Beesitters, the resulting new stable population would in turn be fewer than 100 bees, making 5 Builders account for more than 5% of the population by the time that stability was achieved (similarly, decreasing Builder allocation from 10% to 5% in a population of 100 would result in more Beesitters and an increased population size, making 5 builders less than 5%).
Inviting players to understand and work out how to manage proportional diversity in a scaling/fluctuating population using ratios/percentages was one of my specific goals for Hive Time, but I understand that that's not going to be comfortably accessible to all players. I hope that the explanation helps contextualise why it is the way it is.