Solder in place. It's much easier.
Make sure you have
a) A water sprayer bottle. I pre-spray with water on the wood, etc.
b) A cloth heat shield (around $20) if your joint is, say, less than four inches from combustible material. Putting the cloth in back is fairly cheap insurance.
c) A fire extinguisher nearby.
Once you finish sweating the joint, spray the area with water in case there are embers.
Yes, this is overkill in terms of safety but it's cheap insurance; and it's your house.