check out the blue guppy
https://www.rcgroups.com/forums/showthread.php?1043494-Blu-Guppy-a-96-KFM3-Sailplane
check out Andrew Norton's build of depron that can be used for sailplane
check out Experimental Airlines sailplane build with foamboard- combine Eds techniques with Andrews
check out these gliders on old man rc
https://www.oldguyrc.com/uploads/1/4/9/0/14901388/old_guy_rc_grunau_baby.pdf
Many designs for dollartree foamboard can adapt to depron. You can use packing tape to re-enforce the outside edges of folds...
from a french magazine- with lots of plans
http://jivaro-models.org/mini_loop/page_mini_loop.html
there is a german magazine website with alot of plans for depron sailplanes (those guys are crazy for sailplanes!) but cant remember it now... when i find, i will add it.
also look on rcgroups- lots of plan references there
good luck
gk4rpv