Why would you want to switch between the caps? "one way makes the bass sound nice, the other way makes it sound like it's buried under a dozen duvets. Yeah, I want to keep that setiing!!! ". Hahaha
Anyhow, I've still got a couple of the Mullard "tropical fish" caps left if any of you want to try the mod out. If you prefer the original "wooly" sound, it's just a couple of minutes to return the bass to it's original format.