I am not against using 24v panels and MPPT controler albeit a cheap one, but it was suggested earlier that I will get more out of the 12v/PWM system.
Almot: Old panels will go. they are about 20W if that and wired with 16AWG wire or something similar.
So the plan is for just 2 new panels with the new controler. If I were to go with these
Poly panels from SolarBlvd I wouldnt bother with more panels. There is also an option with two of these
Mono panels but from what I read poly will be a bit better in cloudy conditions.
I am thinking about the
Morningstar SS20L for the controler. I believe this should be enough for the panels chosen. Or the Xantrex C35 that you mentioned if it is better.