What  aluminum arrow size for 48 @ 27  
Mikuta longbow.  I'm shooting spruce 50-55 spine wood now 160 gr.
Probably will shoot 125 field tips and 125 gr 3 blade muzzy bh cut 28.5 long  
I'm thinking 2016 or 2117?

The 2016's spine at 61#, and the 2117's spine at 81#. You might be better off with the 2016 shafts. Leave them a little long to begin with, and trim to the length that gives you the best flight. You might want to consider a 145 grain point, too.

Good luck!

I tried a 2013 it shot straight..It weighed around 424 gr. I don't know what weight  its spined for.  Would that be alittle light?  
I didn't bare shaft though..

If you shoot a dacron string, you can also try a 1916. With a fast flight string, a 2016.