Depends on if your inside or outside.
The amount of defect you have to level.
I love the 105 but it dries fast and you can only do a small area at a time. I use the lake country hydro tech cyan pad and follow with a tangerine w 205 for a flawless finish.
lately ive been workin on a lot of mercedes so i switched to the new lake country hybrid pads but i use the flex and switched to Menzerna super intense which does the job for major swirls and 2000 grit sand marks but i always finish w 3000 grit 3m trizac, i use the blue heavy polish pad then i finish w the white hybrid w 205 then seal w that BLACKFIRE FIRE FIRE which to me is the awesomest sickest wet look yet.....plus i do alot of cquartz also on exotic or high end models.. hope this helped but i only use the PC for sealing w a crimson hydr tech pad , i use the FLEX 90% of my work unless major wetsanding like whole cars.....good luck and GOD BLESS