BE CAREFUL, you are scaring me with that leaning over thought. Seriously, there are ways to get out there that are safe, but I would need some pictures to make suggestions.
I haven't had to do a 45° lately, but in my early days I did poorly. My attempt to do better was to attach a strip of carpet edging to provide a guide to keep me straight. The process is as you asked, one side at a time, but it quickly identified the up and down nature of the rafters and allowed me to fill as opposed to follow the wave. the result was, IMO, very slow, but very good. It probably would have been easier if the framing crew had done a better job of crowning the rafters. next time i will shim and trim before I try to hang.
Bud
I haven't had to do a 45° lately, but in my early days I did poorly. My attempt to do better was to attach a strip of carpet edging to provide a guide to keep me straight. The process is as you asked, one side at a time, but it quickly identified the up and down nature of the rafters and allowed me to fill as opposed to follow the wave. the result was, IMO, very slow, but very good. It probably would have been easier if the framing crew had done a better job of crowning the rafters. next time i will shim and trim before I try to hang.
Bud