I've read that many times, however, I want my paint to work the way it's supposed to work, not have any issues etc. In the end, if you spray good clean coats, let it flow as the clear is designed, I would venture that my 2 coats of clear are no heavier than most guys that are reducing their clear 200%. I don't know how many coats they are applying, but if you want any chance of sanding out paint masking lines you will need to have at least a 4mil film build when dry (this requires an 6 to 8 mil build wet). I like to get about a 5mil dry build, with 2 coats sprayed the way I spray, I get pretty close to that. After wet sanding and polishing I end up with between 2.5 and 3.5mil.
The other issue with over reduced clear, is if you do need to do a spot repair, you run a high risk of wrinkling the existing clear. I weighed the stabs before I painted them today, I'll weigh them again tomorrow after sanding and polishing and let you know how much weight I added to each stab.