Does anyone recommend one formula or brand for this application?
just a good silver solder, no brand i care about in particular, just as long as it is silver solder
i use wbt solder and from what i've read on audioasylum it's considered to be the best, but like jonny said any silver solder should do the trick.
I'll second the wbt. It's worked well for me.
http://partsconnexion.com/catalog/soldertoolscleaner.html
Partsconnexion is a joy to work with. Audioasylum turned me on to wbt and the Cardas quadeutetic solder part # CARDAS- 62034 Cardas 100g roll Solder $11.00
Low melting point, a breeze to work with, and highly recommended. 11 plus shipping from Canada. They are fast. I use them for most of my cable builds.
Good luck and have fun ;D
Kester seems to get some good reviews from Cable Asylum
http://www.partsexpress.com/pe/showdetl.cfm?&User_ID=4483264&St=4291&St2=69845862&St3=64490589&DS_ID=3&Product_ID=10614&DID=7