When I hardwired my reg/rec I made my own copper crimp connectors by wrapping thin copper sheet around a suitable sized drill shank.
I then covered these with glue-lined heatshrink, which both seals and strengthens the joint.
This avoids soldering, which can cause weak points, flux residue corrosion etc.
Its also better than using one-piece crimps already fitted with the glue-lined heatshrink as this gets damaged when you crimp them (and they're too big and bulky anyway).
More recently, I've found these plain copper mini crimps, which wil probably do the same job.
http://www.ebay.co.uk/itm/200Pcs-Cop...AAAOSwn-tZGW0c
Along with the glue-lined heatshrink .. mine came from Kay's fasteners .. ebay.