opps ! oh my.....
trimmed the front to 16mm thought I would get away with that -- they are very tight thought I could take out some of the return to loosen them up, but I mistakenly measured and trimmed the backs of them.
off to WTF to order more upper arms.
how much return edge should there be at the top (shoulder) and bottom (elbow) ?
if I make the front cover strip 15mm is there a maximum for the back ?
my arms are not all that big not sure how I ended up this way but will measure better next go round.