So my biggest issue with capturing an asteroid has been the one claw limitation. You can't use more than one and still get your CoT behind your CoM. You can get it very very close, but it's incredibly tedious. Using a single claw results in a lot of wobble at higher thrust. This would make moving some roids take just shy of forever. So, I built this craft, the RoidMover-WS Mk I (Wobble Stabilization). It's a heavy, um, pusher(?) that can handle up to Class C asteroids, though is less efficient with smaller asteroids; the more surface area the better. Just grab your roid, align your CoM/CoT, lock yer pivot and deploy the stabilization arms! Once deployed, you need only lock the pistons and it will significantly (in my testing) reduce the amount of wobble under thrust with SAS engaged. I was able to get a Class C into LKO with fuel to spare. Now that I have a proof of concept, I am working on a MK II super heavy version which I hope can push Class E.