A question about glass thickness on a lam longbow - Moved th Bowyers Bench

[rich k]

A question about reducing the thickness of fiberglass laminations while increasing the core wood thickness in a laminated longbow.
I have built about one dozen laminated longbows but I no longer have a shop so it is something I am unable to try for myself. I always wondered about this but never got around to testing it. Suppose you have a laminated longbow of 62 inches in length and 45 pounds. The core wood is laminated bamboo and the fiberglass lams are 40 thousandths. If you made a second bow with the exact same design and limb thickness but used 30 thousandths fiberglass lams and increased the core thickness the same amount what would be the result? Would the draw weight decrease? If so, by what amount? Also, what about performance? Would it cast an equal weight arrow at about the same speed? As the physical limb weight would decrease that would suggest possible improved performance.
I recently reduced the weight of one of my longbows from 44# to 38# and it seems to shoot the same arrow at almost the same speed. The arrow has a 150 grain field point and weighs 412 grains. I am getting right around 160 fps at my 28” draw. I reduced the original 40 thousandths glass lams to obtain the 38#. Unfortunately, I didn’t chrono the bow before reducing the weight and have lost my build records in my last move. Of course, I couldn’t increase the thickness of the core wood to make up for the thinner glass.
Any thoughts/ideas will be greatly appreciated.
I sure miss my shop.

[Doug S]

 I'm guessing here but I would think you would lose 1# maybe 2
And hardly any speed. I think the feel of the bow would change so little you might not notice. 
Build it and tell us

[McDave]

From what little I know about making bows, having never made one personally, the action is in the wood lams while the primary purpose of the fiberglass is to hold things together.  So it would make sense to me that you would increase performance by reducing the thickness of the fiberglass lams. The question is, how much can you reduce the thickness of the fiberglass lams while still maintaining the structural integrity of the bow?