If you're wondering about the tenon saw it's because my circular maxes out at a 2" cut (and I'm not sure it really cuts that deep) and anything slightly over this requires some hand intervention.
I've got another problem too, I used the list of required lumber on the website and it's different from that contained in the construction manual. I'm supposed to use 5/4" x 6" for the roof but the website said use 2" x 6" and this is what I've already bought. I can't face taking it back so the roof will be solidly constructed and possibly a little top heavy.