Batteryfaq.org is another good reference, site gets updated about every 6 months.
Seen this one for proper wiring: http://www.smartgauge.co.uk/batt_con.html
We went 3 years with two interstates a year apart in age with no problems. These were 12 volt wired per the smartgauge site. The problem with the interstates was the high absorb voltage required to fully charge them, 15.5 volts
The wally world hybrid deep cycles are a waste of money, they are intended as cranking or trolling batteries not true deep cycle rv applications.
It is best to match the batteries as to make and date of manufacture.