Long time no post--here's a progress photo, got in a bit of a time crunch 'cause I was otherwise engaged (long story) and am cutting some corners. Here's progress to date.
I widened the nose so the wheels would get maximum benefit from the fenders and wouldn't you know? Right after I finished sawing I remembered the suggestion of narrowing the front track instead. Oh well, there are multiple effective cat skinning technologies, as the saying goes.