Raising the value of the filter caps will stiffen the amp up, not loosen it up.
Going from a 7H choke to a 3H choke is going in the right direction, but I have no idea if that would get you what you want. I suspect the change would be subtle.
An easy fix to try: Check where the NFB is connected on the impedance selector. If it's on the 16 ohm tap or connected to the speaker jack, try moving it to the 8 or 4 ohm tap. As you move from the 16 ohm down to the 8 or 4 ohm, the feel will loosen up a bit, and the tone will get a little gainy-er / hairy-er, and a little brighter.
The newest BE100, I believe, has the NFB connected to the 4ohm tap and they are a little more aggressive sounding than the older ones.
If you want to mess with the filter caps, see what value cap you have on the screens, and you could maybe lower that cap to get more sag. I wouldn't go lower than 16UF though.