1) I would love a ROHAN database with more information. Like drop tables and descriptions of gear stats (max stat information).
3) It depends on the stats - you need to keep checking the current market all the time. Right now it's like this:
19x pdef (non ench) parts are selling for around 1 - 1.1k.
19x pdef (ench, hp +5) around 3.5k.
11x pdef (ench, hp +5) are selling for 750 rps mostly.
The higher the + the better ofc.