Were aircraft plywood is specified in the plans there is no logical room for argument about what plywood to use and that plywood is readily available today. If however the plans specify a marine grade of plywood for a part then it is also logical to use the marine grade if it is available. I do not know if the marine grade of plywood specified in the plans is the same marine plywood being sold today (VP plans are circa 1960). Further there are at least 3 types of marine mahogany plywood (1) Okoume 12lbs 5/32"x4'x8' sheet,(2) Sapele 20lbs 5/32"x4'x8' sheet, and (3) Lauan also called Merranti 21lbs 5/32"x4'x8' sheet (I use 5/32" for example because they all come in that size). Aircraft mahogany plywood in 1/8" and 3/16" is 12lbs and 24lbs respectively and I surmise 5/32" would weigh 18lbs if it was made. The strength of sound wood is closely associated with it's weight and there is quite a difference in weight of the different plywoods for the same size so I imagine quite a range of strength as well. What are other people doing to address this issue? Also the plans call out for A-A grade marine plywood, I have not seen anything but A-B grade for any of the marine plywood available. also how is this being addressed? Thank you.