Between close of transition, wave start and my bike times, I could have that kind of loss in a long course race. I don't understand how latex is feasible if this is correct.
It is simple to adjust for... For argument's sake, lets say you lose 1 PSI/hour. So, when you pump up the tires before the race, simply add 1 PSI for every hour you expect from that point in time until you start your bike. Then, if it is a long course, assume you will lose 5 PSI. So, add another 2.5 PSI to average your target PSI.
At race time, you will average your target PSI and be within Â±2.5 of your target. That is not too shabby. And, it is inconsequential, given that latex is faster than butyl.
If you enter a race where you cannot pump your tires race morning, then I would use butyl. But that would be stupid of the RD to disallow racers from tuning their tire pressure for the morning conditions.