Barbell vs Dumbbell Presses. Less Triceps, More Chest/Delt?

I agree with Angus. If I do some cross-overs, or flies for chest during my warm ups, or before barbell bench pressing, I feel my pecs working a lot more, when I bench press the barbell.

Now, I don’t really think about “pre-exhausting” the muscle. I think of it more like a specific warm-up, almost like a pep-talk for my pecs. “O.K. chest, we’re about to bench, so wake up!”

Also, lots of guys like slight incline or slight decline bench pressing, with barbells or dumbbells to hit more chest.

Bar Speed, my opinion;
Don’t slow down on “big” exercises like bench presses or overhead press. As you said, don’t distort your Technique. Pausing at the bottom is useful though.

For isolation moves, like flies and rear delt raises, pause, or go slow on negatives, or whatever. Use Form to keep tension on your muscles.

Lastly, having big triceps, and being tricep dominant in your pressing doesn’t have to be a bad thing. Lots of strong guys train for that specifically.