BEST WAY TO SHOW A CUSTOM GAUGE IN BATTLE? (RM2K3)

I'm trying to figure out what the best way is to show a gauge that builds up gradually during battle in the DBS in RM2k3.

Basically it kind of acts as a communal MP pool, but the specifics of what it's there for aren't really important, I guess. It's just a percentage bar that I want to put in the upper right hand corner of the screen that goes between 0-100% essentially.

So far the ideas I've had have been:

using the battle background itself and editing the gauge into it as some other games have done, the only problem is I would need either 100 different battlebackgrounds for each percentage point in each area, which would mean literally thousands of battle BGs, or say ten or so each and a much less accurate gauge that only reads in increments of ten, which still means a lot of battle BGs but I suppose would be doable. I don't really like this idea as it kind of limits my options with the system I had in mind, but I guess if it comes down to this it may be what I do.

Idea two was to call a common event to show a picture in battle since there is no "show picture" option in the battle events themselves, but I'm not sure this would work and I haven't had time to test it out yet. Can anyone tell me if it's possible to show a picture in battle at all?

Idea three is battle animations, run as a common event parallel process to show the gauge. The issue here is potential slowdown of the battle and weird overlapping of attack animations and the gauge itself, but this is the one that allows for me to have a gauge that's accurate to 1%.

Which one of these seems most plausible and least intrusive in terms of causing slowdown? I'm leaning towards battle animations, but I'm afraid that this is going to end up causing the battles themselves to lag because I'll have to do it as a parallel process. Any other options/advice/help would be greatly appreciated.

Thanks.