OK so i think i solved my mystery squeel...
Loosened the pinch bolt, then snugged up the main axle nut to eliminate the one mm of play that the speedo drive had between the wheel and fork. Then i took it out for a spin just as it started to freezing rain... got it to 40 once on a straightaway just to try and recreate the squeal (the in-lane lean/sway). I didn't hear anything so I assume the problem is fixed. I didn't want to stay out very long since it was pretty awful riding conditions, but I'm pretty sure I fixed my mystery squeal.
On a side note, is there a maximum torque setting for the front or rear axle? I don't want to be aggravating another problem by my assumed fix of this issue-
I've seen this axle torque listed for other bikes, but not for enfields and there's nothing in my super factory manual about it... I didn't crank it very tight, just enough to take up the small amount of play.
thanks!