This is what leads me to think I might enjoy mbld even more than 3bld. I tend to memo so carefully that it sticks which doesn't lend itself to speed but I don't have to review much or at all unless I know there's a mistake.
I see the wisdom of "memo faster, review more" that you shared in the past for 3bld and I expect that'll start happening more with practice/confidence, but to this point I still memo 3bld as if I need to retain it for 10 mins or more (because initially I did).
If you think about it, it's not just memo timing what you're referring to memo. Most cases, 10+ & 7+ letters, making images out of ~20 letters are not that time consuming. On top of that, if you keep practicing, you're running into similar letter pairs so often, you don't need to make up new images any more (not completely but more or less). There are "only" 400+ letter pairs, after all. So, at your stage, the most time consuming part, I guess, is actual tracing rather than memo.
And for 3BLD, the wisdom is just memo faster not so much of review. Review more part is for MBLD only. The only way to push your memo time and make it quick and faster is not reviewing what you just memorized.
I'm curious to get a high-level idea of how you utilize rooms for mbld. I understand the general concept but whatever you're specifically doing is sure working for you!
You make images based on objects in your room. For 10 cube MBLD, I use 20 different places in my home, assigning each room/place to one edge or corner of each cube. And I make my rule to go around those places in a sequence I always follow. Start from my study shelf, desk, closet, walk to living room shelf, window seat, and so on. This sequence is always the same.
And, for example, my first letter sequence is like: TR - SC - MY - PB - EL.
And I'm trying to link this cube (edge pieces) to my study shelf. There is a TRophy from last Summer Comp where I've got MY PB of ELeven two.(I've never been a podium - so obviously, this is a make-up
). You build images of several cubes like this, and each cube (edges and corners) to a different rooms and objects.
When you finish your first cube, then move to the next room/place, and use the image you built up from there to recall what letter sequence was.
Not sure whether it makes sense to you, but this is at least how I do multi.
. I have a spreadsheet where I'm collecting my letter pair images and it's definitely more than half filled-out, maybe even as much as two thirds. I actually started learning 3bld back in Jan but I've had a handful of breaks in practice so it has been two steps forward, one step back. As a result, my collected image list is much farther along than I am. 
