350 Sebring 6V to 12V conversion question

[Nick]

I've converted my Sebring to 12V by joining the two AC leads from the alt. and have hooked them to an old Honda rectifier. Coil, etc. also changed, the bike runs great. However, a voltmeter on the battery shows that it seems to overcharge (more than 15V) and it blows headlights (I run a sealed beam automotive unit). At present there is no regulator in the system and the rectifier is not grounded (I was told not to ground it with this set-up.) I've ditched most of the stock wiring except for the ignition key. Lights are run off a toggle via the stock hi/lo switch.
Question 1: Can I simply hook up a mighty mite electronic regulator/rectifier? If so, should I ground it, or not?

Q2: If wires of different gauge are used in my home-made loom, can that cause excessive loads that might blow a headlight?

Any info greatly appreciated. For anyone with a Sebring sitting around in the garage, I heartily recommend ditching the stock carb for a slightly larger bore Mikuni. My bike runs very well with this set-up, has 2 or 3 more HP, starts and idles well and gets 75 mpg.