cray, what do you have and what are you looking for as far as trigger pull weight? Tom, you said Para, but what pull weight are you looking for?
Also, what is your time schedule? I may be able to help.
I've used two of the four above-mentioned smiths and was satisfied with the work, but I haven't used any of them for 1911 triggers. I'm not saying they can't do it by any means; just stating that up front.
If you want any major improvement, you'll probably have to replace the hammer, sear, and sear spring (and usually the disconnector). With Para (and Kimber, and many other factory 1911's), the hammer and sear are MIM. If you put them in the jig and clean up the engagement surfaces or cut the angles (anything more than lightly polishing), you basically are cutting through the hardness of the part and the trigger job won't last for a long time. If you are just doing a modest improvement, you might can get by just tweaking (or maybe replacing and tuning) the sear spring.