My suggestion if you are going with Solar Blvd, is to buy a pair of their square or close to square 140W 12v panels. Then go on Ebay or Amazon and buy a good 20 amp or 30 amp pwm Charge controller for around $30 to $35. Solar 30s are nice, there's also a nice $32 20 amp version on Amazon that I bought recently and really like, as it's adjustable voltage and able to do equalize charging at a full 16.0V
Put some door hinges on your two panels, and a latch or two to hold them together. Mount your charge controller away from the fumes of your battery while charging, but as close as possible to the batteries without getting corrosive gassed out. Use some 8 or 10 gauge wire between charge controller and batteries. Try to keep the run down to 3 or 4 feet max.
Wire gauge between panels and charge controller is not too critical, maybe use some Home Depot Malibu lightw 12v low voltage wire for your run from your portable panels to your charge controller.
Anderson plugs are nice for quick connect / disconnect features.
Always hook your charge controller up to the batteries first before hooking up to your solar panels.
Throw towels over your solar panels before plugging them in to the charge controller, to cut the amps before starting charging. They are live or hot as soon as it's daylight and skylight is shining on them, rain or shine.