DIY it, I know you said you don't wanna, but most of this opinion are against the sanding mess mostly. So don't sand as stated by a few others, I once had a job doing the property maintenance/upgrades older facility that the company wanted to constantly bump up a notch. So I ended up doing quite a box drywall repair/changes, what I learned is thin coats, do only an area that allows you to circle back and clean the sometimes big build ups with your knife while the material was "green" (not yet cured but getting close), peels off the lumps with little mess to clean mostly solids that were easy to sweep up. Depending on overall size you may even get 2 rounds of build ups that will require little sanding. I'm still a long ways from no sanding finish though. The knife work will make you a better bondo slinger as well! In case that is a concern Harry P.S. use a fine filter on your vacuum that is cement like material that will grind down the armature and brushes, voiding any remaining warranty and seriously shortening its life!
