I have the "Warm N Safe" heated base layer - excellent bit of kit! The base layer draws less current than the jacket so I plugged the cable into the DIN socket under the pillion seat, that way I can remove the cabling in the summer. The socket rating is OK for 5Amp I believe (its in the handbook for the 1260) but less if you have spotlights fitted. According to the Base layer instructions it is about 3 Amps so well with the available amperage for the DIN sockets.
Using the supplied sockets is imo the way to go. If the bolt on the battery terminal is a bit marginal length wise, why not just buy a couple of longer bolts...
While my bike was in for a service, I got the dealer to wire my Keis lead to the bike. He fixed it very neatly to the power feed to the accessory socket this avoiding cluttering the battery posts.
Used the W&S battery harness and then got the little adaptor for my optimate cable. Works a treat. Jacket is so warm. Gloves are good and keep the cold off you especially with the 1200s heated grips.
