Jack,
I have had sucess with Simpson's, Val Spar, Dunn-Edwards, Sherwin Williams, Mac Lac, and US Cellulose lacquers. Right now I'm using Val Spar or Mac Lac. I work for Dunn-Edwards Paints and we no longer make our own lacquers and I sell both of the products. I like them both for the purpose of doing a Relic.
My suggestion is to call your local paint manufacture and ask for High Solids Production Grade Lacquer. It yellows real fast and does not take abuse very well so it relic's quick. Pop the can and make sure it looks like honey, if it is a clear as water it is not the right stuff. If you can get 680 VOC in the area you live get it, if not 680 VOC, 550 VOC works fine, you just have to blend more thinners like retarder and butyl into it. If you have to use 275 VOC think real hard about looking somewhere else for the product. Do not let them sell you Pre Catalyzed Lacquer, or Conversion Varnish.
If you want to keep the guitar pretty for longer use the producton stuff on the first coats and then do the last 2 coats with McFaddens. The production lacquer will still yellow out but the McFaddens is a higher grade lacquer and will hold up to abuse a little better.
Good luck
