Since release 1.9.11 the default config.height has been 37, I really hope that was a typo as it looks really strange depending on the number of bars you have. With a low amount you can clearly work out what they are but then they start becoming undecipherable.

Ideally we'd be able to have this dynamically set by config.staticheight / #bars shown with a minimum value of about 17. No idea if that is possible to do though.
Alternatively work out an average amount of bars expected to be shown and divide config.staticheight by that.

This is what it looks like for a druid depending on spec/stance/affinity, these aren't all likely scenarios but that was the easiest way to get a different number of bars and a consistent size.

Trying out config.height = 20 and config.staticframes = 7

Further thoughts, prompted by my comment about capping recharge bars to three from #3

If the size of the window was dynamic in a different way would that work better?
I'm thinking of a bar/icon size of 18 as that would make recharge timers 6 high and is pretty clear to read. Then if you can set the config.staticheight to #bars shown * 18 it would avoid the strange stretched icon problems. I suppose you might want to have a max_config.staticheight to stop things getting crazy and then go back to dynamic bar heights within the max height.