There's so many ways to do stuff.
I'd recommend focusing on the basics like making sure you have really good low resistance connection points. That means no corrosion / oxidation, good crimps. Also, use adequate or even better than adequate wire gauge to minimize voltage drop and maximize current carrying ability.
A bi-directional automatic relay might be had for the same or lower cost than a typical isolator. Isolators typically cause some voltage drop which makes it more challenging to get the house battery fully charged. I'm pleased with the low cost relay I posted about here:
http://www.classbforum.com/forums/f8...lled-3409.html