So, you tried 55-60 and 60-65 and then jumped to 80-85????
Ok, let's see.
Your bow is 55#28, you draw 27". I assume you shoot around 7-7.5" brace height as shown in second post. Then you should end up at : (55/28-7)x20=52#@27.
FF Material? I assume yes. Then +8#.
.5" over 28=+2.5#; per 25 grains over 125grain add #5 pounds, so 35/25=7#.
Now, if your bow is cut to center and not slightly before center like normal longbows are, then I would add 5-7#.
Adding up: 52#+8#+2.5#+7#+(5# to 7#)= 74-76
Now, get a test set from Elite arrows with 73#- 73#-77# arrows. Get those full length and start cutting them down from 29" in 1/4" increments.
I wouldn't trust your test shafts too much, as we can't see the quality and thus spine readings are questionable.
If you require really 80 to 85 and still showing weak, your realese is probably not the best or do you have a groove in your glove?