I also had 2 HT boys, one was on vidalta at first, the other on felimazole.
We moved to felimazole for both as it was easier to tweak dosage, which you will know you have to do if the T4 creeps back up. It also seemed to work far better for my 2.
Felimazole is good because you can get a transdermal gel to rub in the ear if they get tricky with pills.
Jake had no issues on vidalta, I also heard scary stuff about it & was worried.
Did your vet give any reason for starting on vidalta rather than felimazole?