One thing that some coaches (Joe DeFranco is one) like to do is to follow up a heavy barbell set with higher-rep, lower-intensity unilateral work. For example, 3x3 barbell bench (after warmup) and then 3x8 dumbell bench. But then of course you’d kind of be getting away from the program a little bit. I know a lot of top powerlifters mix in dumbell work every few weeks, you’re not going to tax your maximal strength as much, but it might help fix imbalances and build up the stabilizers a little bit. If you haven’t done a whole lot of heavy dumbell work I wouldn’t be surprised to see you get some good gains from doing the switches you proposed for a few weeks. Try it and post on how it works?