Alright a tad frustrated now.

Got my SimpleCalculator.ascx in my usercontrols folder and went back and added strong signing to the control, rebuilt, copied the dll to the GAC in c:\windows\assemblies got the public key from that dll's properties went to the web.config and added a line to the 'safecontrol' with the appropriate namespace, public key, etc. - and lo and behold still a parser error that says "could not load type 'SimpleCalculator.SimpleCalculator'", alas this is discouraging.