CCA = Cold Cranking Amps; 500cca @ 12V is what it's
capable of, all that means is it won't go flat as quick but, it also means it will take longer to recharge...
Using the fuel tank analogy again, the fuel is still running through a 1/4" hose, which controls the flow rate (which is akin to voltage)it doesn't flow much quicker just because there's more fluid behind it (the amount of fuel is akin to amperage)...
Now, there's likely to be one or two who will jump in & say "no, the size of the hose = resistence" or something like that but, for this exercise, it works...
Having said that, you're probably best to find a smaller battery if, for no other reason than to reduce weight...
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I was working in a panel shop some years ago when a project arrived, a '78 Corvette with at least 15 different colours on it (no, I'm not exaggerating, the paint was 1/4" thick!). The boss pondered what was the "best" way (meaning the quickest, most cost effective way) & finally decided on bead blasting. Bead blasting is a lot gentler than sand blasting a can be more accurately pressure regulated to only remove what material is necessary...
Having said that,
it's not cheap & I'm not sure it would be cost effective for you so, I suggest you invest in
one of these & some 80-120grit discs to suit. If you're lucky enough, you'll find a shop vac to fit where the dust bag attaches to remove the majority of the dust as you create it...