My Deltran battery Tender Plus is on its last leg, Wanted to try something different this time around. I went to the CTEK website to make a selection and now my head hurts. Which CTEk charger is best suited for the FGT, still on the OEM Optima battery which I suspect its going to need replacement pretty soon, not 100% sure what the replacement is going to be as Sears' Die Hard is no longer available. (I have Kendall's "quick" connect/disconnect kit installed). Thanks !