In my '55, the original battery tray was still good, but I decided to make my own tray out of angle-iron, mitre cut and welded. I primered it with rust-olem red-oxide metal primer then used two coats of epoxy spray paint for home appliances. That was many decades ago and it still looks like I just finished it yesterday.
Have someone check your voltage regulator output to see if the charging rate is too high. If so, excessive acid bubbles will emerge from the battery fill caps and prematurely corrode surrounding metal parts. There's always going to be some emergence of acid, but as properly set regulator can minimize the damage.
Use of felt washers on the battery terminal posts is also helpful. These are sold at most chain auto parts stores (one red for positive terminal and one green for negative terminal), sold in a set.
Initial removal of corrosion from lead battery cable terminals can be accomplished by soaking the terminal in a plastic container of hot water mixed with baking soda. This neutralizes the acid and annihilates the white puffy corrosion. Afterwards, you just buff the cable terminal with a wire brush to shine it up to get good contact.