I just put an Optima in my Healey. It was donor from a home security companys back up generator. They change them out about every three years. The generator gets test fired once a month, otherwise they sit with a manitainer until called into service. I was very suprised to find the battery output was still more than a new standard battery. After sitting on the floor for several months, it was finally put to use. I cant say for the price to buy a new one I could go this route, but for what it cost me I cant complain. Normally I would use a group 27, but dont have any concerns with the Optima posts shorting to body if battery shifts.
My forklift sits more than used. After a couple years from little use the battery usually just quits, without any warning, even if maintained and wont charge for any length of time. Its hard for me coughing up the cost for a premium battery, but I think one would have a long shelf life for this. Fortunately, a buddy sells surplus and blems for $25. In the long run for the forklift, its way cheaper to go this way, but for my Healey, I dont want the battery to take a dump out on a joyride.
Dont know if its a gelcell or AGM, but the Optima is a completely sealed case. I would usually consider an Interstate, but even those leak and corrode terminals more than I would like. Especially if you dont keep check on a regualr basis.