Hi and thanks for your questions.
Right now there is no easy way to make presets that just span a subset of controls. There are some ways around this that would send certain values for a lot of controls, but no options that will allow you to send CURRENT values for a set of controls. To be honest, I hadn't thought about this possibility. I will add it to the queue of possible features, but I'm pretty sure it's subsumed under the not-yet-existing feature: presets for a group of controls (right now they are rig wide).
[I might think about some workarounds for this. Of course, sending the value of a whole bunch of buttons is possible via momentary butttons and super-sub controls, but it won't take the current value of a control. Actually it might work in your case: supercontrol is momentary button, subcontrols are momentary buttons with "send on only" selected.]
Regarding your second question, you can already do this (but only by time). Check this question and see if it works. If not, comment there and I'll flesh out the answer.
Thanks for using MIDI Designer and for your questions.
Best!
Dan