Mark Macy does it professionally, I believe. I've not dealt with him myself, but he seems very professional and I've never heard any complaints about his work.
But having done it myself with only the workshop manual, I'd say go ahead and tackle it. The only hard part is getting the drop arm off the shaft, and using a proper Pitman arm puller (instead of the makeshift arrangement I had) should simplify that considerably. Make sure the top cover adjustment is loose (or better yet have the top cover off) while setting the end play. I wound up using a dial indicator to set the end play (insert extra shim, measure end play, remove shims equal to measured play).
Enco usually has an acceptable quality dial indicator and magnetic base on sale for under $25. But it seems they are only available separately at the moment, for a bit more money.
http://www.use-enco.com/CGI/INSRIT?PMAKA=605-4070&PMPXNO=949084&PARTPG=INLMK32http://www.use-enco.com/CGI/INSRIT?PMAKA=625-0300&PMPXNO=946102&PARTPG=INLMK32