I'm not a vet, but I've had to deal with this before. I tied a thin doctor's string around the warts and they eventually fell off. Everyday I would clean the area around the warts to be safe. But don't listen to me, I may be wrong.
I definitely go for winning rate of gain. I find it the most fun beefing up my steers. My friend tom and i usually compete for the prize. As for my stategy, I just weigh em in and the following week start with a new feed. :-\