I put up a posting in regards to what Rocket head to shoot based on 100 grains but I just went to a site and figured my FOC and here is what I came up with:
ACC 3-49 28 1/2", 3-3" vanes with 100 grain head = 387 grain arrow with a FOC of 9.4, now the same arrow with an 85 grain head = 372 grain arrow with a FOC of 7.9.
Now, would the 85 grain arrow be better than the 100 grain ??

Bow setup: 70 lb Pat with a 29" draw, Trophy Taker Shakey rest, Arrow being released by a Scott Little Goose release.
I want to shoot Rocket Expandable's so if I should go with the 85 grain heads then which one's?? If I should stay with 100 grain then which one's??

I know that bow season is right around the corner but I have been extremely busy so can I get some quick professional opinions on this PLEASE!!!!

Generally an foc of 10-12 is recommended, so based on this I'd choose the 100 grain head. However, with low profile field tips and mechanicals, it sometimes isn't as much of an issue. Any chance you can screw on a 100 and an 85 grain field tip and see how they fly for you? If not, I'd shoot the 100 grain and go from there.