I do not have very much experience with dope yet.  I am new to the hobby and crashing is my best stunt.  Working on a somewhat Fancherized Twister/ Allen Brickhaus Scimitar and want to cover the twin rudders with silkspan.  They are 3/16 medium balsa cut on a 45 degree grain.  I have butyrate dope and I also have Minwax polycrylic.  Or I could just use dope and forget covering it.  I am planning on covering the fuse and stab/elevator with silkspan and dope and polyspan on the wings. 
I appreciate your help.
Best Regards,
Charles

I use thinned Butyrate dope and silk span/poly-span on 1/8 balsa covered both sides.   You need to go light with the first coats of dope on rudders, stabs and elevators  Do one side then the other almost immediately.  Once you get enough dope on, like three coats lightly sand the roughness.  I you go to heavy on one side they will warp but it can be remove with more coats on other side.  It takes practice.