Just a thought...
I have a SIG Skyray 35 kit new-in-box. The plans are traditional SIG quality, i. e., excellent!
If SIG no longer has the kits or plans available, and they have no objection to others filling that gap ( I'll check, but as I paid them for the kit, I should be okay cutting a "working copy" for my use or "loan" to others.) If all this is the case, I'd ask no more than my cost to copy and mail them to others - one by one, at no profit to me.
I will, and you can, check the SIG Manufacturing website. Search for anything near that should get you there, and it IS always best to attempt to go to the originator first.
I believe my email is available through this site. If not, find a way to PM me, and we can pursue it further... The Skyray 35 is definitely worth such effort!