I have a three year old Shorai that works very well....However...
My bike is dead when I shut the key off. No current draw.
These batteries are awesome. I dont suspect there is much difference in any of them.
What they say you cant do is ever let them run completely flat. That could be a problem, in your situation if you parked your bike, and left it for.....
And thats the issue.
Not sure how long you could go with that alarm drawing juice from the battery before it ran so low it became a problem.
If you were to get the battery, and the companies charger, that should work well. The alarm can do its thing, and drain the battery, but as soon as it runs low enough, the charger kicks in and tops up the battery.
I chose the shorai for two reasons. One, it comes in a nice, heavy duty , plastic box. Its easy to mount in a battery box.
Two, there was not as many to choose from, back then.
The shorai brand has an optional charger that would work well for what you are doing. Also, it hooks up and balances the individual cells of the pack.
I imagine they all have this feature, but back then, it was harder to find.