You have been to CDave's site? It's linked in a sticky at the top of this forum in a thread entitled, 'Every kdx rider should read....'
You will find the answer to your questions there.
Not sure why you think oem jetting is 52/155. Never has been. Doubt '05 is different. It could have been changed by the dealer...in which case, don't ever go back there 'cuz they're boobs. There is NO way a 52 pilot is correct.
BTW..'1:FMF Gnarly' doesn't mean anything in regard to a jetting question. FmF is a brand name, 'Gnarly' refers to the metal guage used to make it. It doesn't indicate what pipe profile you have...and the two profiles available from FmF jet differently. The torque pipe jets considerably more lean than the rev pipe.
re: 'what would be the next step..'
Set-up your suspension if you haven't already. Actually, that should have been step #2, right after you took the thing apart and put grease where it's supposed to go.
With variances such as fuel, riding style...even how you oil your air filter being critical to correct jetting selection, there are only two people that can tell you what jets to run: 1. You, and 2. The professional tuner that's watching you ride and listening to your lucid, comprehensive description of how the bike is working.
Bet'cha don't have a #2, 'eh? ;)
You might want to concentrate on #1.