Using different batteries and solar chargers questions

Update:

I took a drive to Solar Blvd and purchased the 120W portable kit for $190. The kit comes assembled and prewired as shown in the pics in the link below. The legs for tilting the panels are rather flimsy, but they should work. My kit did not come with the light bulb accessory shown in the pics, but I'd rather have the extra 20 watts than the light bulb. Due to rain and cloudy skies, I won't be able to test the system until the skies clear. Pictures

Batteries:

My local Interstate Batteries distributor wants $108 plus $18 core charge for the exact battery that came with the TT. :E I can get a Costco battery with the same RC 140 rating for $75 and $9 core charge. Needless to say, I'm getting the Costco battery.

Correct me if I'm wrong; When I connect the batteries together, I connect positive to positive and negative to negative. Right?