Howdy! I went with a Briggs and Stratton 23 hp in the repower. The repower has worked beyond expectations and I look for excuses to use the tractor. The light I bought is here:
Amazon.com : GLW® 10w 12v Ac or Dc Warm White Led Flood Light Waterproof Outdoor Lights 750lm 80w Halogen Bulb Equivalent Black Case : Patio, Lawn & Garden
It's not insanely powerful, but cheap, and about as powerful as the original bulb lights that came with the tractor. The low current draw is a plus. $9 bucks you can't lose.