I've seen no real benefit to using thicker glass lams. I use .040 usually. Sometimes .050 on the heavier draw weight/thicker stacked longbows.
Oh, and by the way, the streaking problem? That had nothing to do with the thickness they were ground to prior to shipment. It was due to earlier construction processes and was present in the thicker glass as well. I heard the last run was clearer, but I haven't tried it yet.
BigJim said he got a good batch in last time, maybe contact him.