wow if hes drawing 32 on trad equipment that is indeed long. generally i think the equation is 2xdrawlength+10%, so 70.4 for a longbow. if you were to build an osage with sinew and/or horn, you could go a good bit shorter. if it were me id make sure hes draw is really that long first, then build accordingly to what materials i had/could get easily. ive seen a 54 inch hickory pyramid drawing 48@ 28", it bent through the handle a little though, which would shorten the length needed by a good bit.