i use my deadblow hammer from Snap-On...slammed down on some concrete (bay floor)....then solder it, never have problems
4ga, 2ga, 1/0...whatever
ring terminals for 1/0 neat trick...get some copper pipe with an internal size to match the 1/0 when stripped of insulation...cut a 1-1.25" piece, insert about 1/2" of stripped wire and hammer it flat...then drill out a bolt hole in the unused half with a unibit
much cheaper than ordering, and wonderful for last minute "oh s***, we dont have 'em" situations