If you are only using a numpad and hot keys (not other characters at the time), then you could activate the numpad layer and customize the left blade to hot keys. However, the numpad lock is not permanent. If you don't hit a key for awhile (I don't recall how long, but maybe 2 minutes?), it will unlock. Same thing with Edit Lock.
There are other approaches. For example, I use the emoji layer for some special things. Or the function layer. These require hitting a chord to access the layer each time and there is no lock.
Another approach would be to set up a jump chord just for when you need these special things (which won't work if they happen intermittently. But would work fine if you go long stretches where you need special things, but not the regular stuff. You simply press the jump chord, wait a couple seconds, and resume with the new layout to the same device (I have 3 layouts connected to my iMac).
Heck, considering the size of the TB, some people may even find it useful to have two TBs connected the same device. Might not be good for many, but it may work for some.