As far as which is easier, liquid or powder... If you put it into a 2-liter bottle or similar where the cover will fit well, there shouldn't be any difference. Check my post a bit earlier. I didn't need to do any buffing other than the mandatory "let's see what buffing does", and the phone looks awesome.
This one shows some of the purple because of the flash, but I guess it's more like the one above.
