There are other ways to separate different sized particles than plain sieving. An up-flow of air can be used to loosen and carry away dust to a collector. Coal used to be separated simply by dropping it down a long tube with rotating spokes - the larger particles being given a bump to knock them down side chutes.
I expect there are other novel approaches
Thickness of the timber, time of immersion, temperature, density - these are all variables when determining the penetration of hot wax. Air expands according to Boyles Law . State of equilibrium is necessary and the voids ideally need to remain as full of was as possible.
Omf’s a waste of time? Please, don’t be starting that again. The ambient temperature at the floor level will be the same with an OMF as with a solid floor in most situations (and most certainly in still air). Most frosts occur at low wind speeds. Wintering hives should be positioned for maximum shelter from the elements. Agreed that an OMF has far more ventilation than necessary, but the air turbulence above the OMF will not be usually that severe, Bees cluster within the confines of the comb, which will reduce any air exchange within the structure. OMF heat loss by radiation is likely as important as the ventilation aspect. I would accept that radiation losses are higher than solid floors, but is that a significant loss? I doubt it.