The "special" tool some use is a 2 X 4 (ha ha); I've only spread (or constricted) rears (hope that doesn't sound dirty); to do it well, a solid axle with nuts on the inside that you "turn out" would be my choice since it can be done equally and incrementally. Make sure you have a torque arm on the fork (even two if, but probably not, feasible). Look at endless sphere for set-ups with small hub motors (like the Q 100); I think the S06P controller can be matched with the small motors easily, but I haven't done it. My front conversions have been Dillenger (which doesn't seem to service the US like they used to) and eBikeling (which doesn't have 20" systems AFAIK).
One other thing that might factor in: AIR, Tern had front fork problems breaking with some of their bikes. If by chance you have one of those models, I wouldn't even consider a front hub system.
Last edited by 2old; 12-25-19 at 12:04 PM.