When comp training, 1-2 times a week would be the max if you're training in the gym also. If you're just doing events 3x a week, then it's possible, but I would watch the leg and lower back recovery levels.
One good way that's always worked well, especially if the two events are in the show is to work superyoke first for your leg/hip strength and endurance and then work the farmer's. This helps for both speed and the endurance needed on both events. Almost any competitor can lift the 250+ lbs. in each hand for a show, the main question is who has the fastest feet and the most endurance with the weight.
The other issue is turns, which usually need to be practiced extensively. 5/10 (4/10 are straight up grip strength, and the other one is someone who can't walk, as happened to me in a show a couple of years ago when I tripped over my own feet!!!)drops in a show happen because the competitor's turn got screwed up and they had to waste precious grip strength fixing the momentum of the cylinders. You can either turn wide to keep your momentum going or slow down and make a short turn.
Either way, the cylinders have to turn with you and you have to make sure their momentum stops after the turn. The best way is to turn your wrists in slightly to get the cylinders going and then turn them back, but it definitely takes practice. That's where the second workout for speed and technique during the week would come in.