6 day split question

[RichVerner]

Hey guys, i have a question about Arnold's 6 day pre Mr Olympia split routine. I changed a bit of it to suit me. Instead of doing arms AND shoulders on Tuesday and Friday...i do shoulders on Wednesday and Saturday along with lower body. So here's my question because I'm 36 and cannot do all the daily volume...unless i have the day off and i could split it up. So say it's a Tuesday, arms, bi's and tri's. Is 20 sets enough for Tuesdays and Fridays? I other words maybye 5×10 of barbell curls, dumbbell curls, skull crushers and 2 arm TRI extensions,? Or should I be doing more sets? Thanks so much 8)