How’s your bulk going? I remember I spoke to you via PM a while back.
I think that rather than incorporating flyes, you could try and put in sets of decline dumbbell bench on the RE (3xMax reps) days. Make sure you press with a neutral (palms facing inward grip) as this has the greatest carry over to the bench.
You could also try slide push ups using chains or blast straps (if you’ve got a linoleum floor and some towels that’ll work too). There’s a description of how and why to perform them in this article by CW:
Yes flies can be a great assistance exercise after the real work is done. Many of the big fella at westside that lift raw use them as an assistance. add them to either day