Welcome, Luke.
Yeah, I can relate to the focusing difficulty. I attributed it to astigmatism as well, until I found out I have spasms in the focusing muscles of both my eyes. What can I say, except get a good focusing screen for your TLRs!
Good luck with your self portraits, I'm certainly glad I did mine... Once you can bear to be in front of the lens, you can work with other people much more easily, at least that's my experience. It sure ain't easy, though...
Anyway, welcome, and post your work!
André