Ultimately my main concern is I just don't want lossy terminations. I have some "posh" coax and plugs coming, extremely low loss coax and plan to make 1 patch lead and a longer run of it so want to make the best of the soldering. Luckily I still have some lead solder which makes life easier.
I hope those posh plugs are Amphenol ones. They're the best by far. If it is Amphenol ones there won't be any loss because they're perfectly machined to spec so as long as your coax is to spec you'll feel the slightest of resistance as you insert to the coax into the plug. Any soldering is therefore just to hold the coax in place. I use solder that's about 0.6mm diameter OTTOMH and use about 1-1.5cm of that when doing the tip.