Great news on Mr Surfacer, er, "surfacing" again.
I also use tamiya luquid primer, you have to try stuff out, see what works for you best. I cannot ever get "Zap a gap" to work for me, for example. I use the "harder" putty to fill in most of the sink holes/flaws, wait couple days for the putty to dry and SHRINK, then top off with tamiya liquid primer.
Some info on Mr Surfacer from Swammys site:
http://www.swannysmodels.com/Surfacer.html