I use screws as well but not for structural members with lateral forces. They don’t have the shear strength of a 16d nail. It is nice to not jar everything with pounding. A lot of times I tack things together with a Paslode finish nailer driving 2.5″ nails, then come back with a heavier fastener. The torque from driving thousands of screws overs the years starts to bother my tendonitis.
I’ve worked alone for so long I have methods to help me handle heavy loads. Like with the header after I had one end on the jack stud and in the socket. I put a post under the header and used it as as jack. That gave me a hands free opportunity to use my 12lb sledge and drive it under the top plate and into place.
As for the 30 year old, well I’m past that on all accounts, not that I’m fat, in fact I lost 15 lbs last year.