Long , i think long is better for slower cars as you get that long straight to get a tow and good passing ops in the first few corners.
Going by memory here tho, i havn't been on iracing since last winter.
The long verson does have a familiar feel to Lime rock through the last 4-5 turns, and T1 has an Okayama feel to it. Will be a good track for racing and not to hard to learn.
edit: Just looked up the course layout , the short version is called Jefferson which was fun also in the mx5.
Maybe do long one week then Jefferson the week after as would make it easier to learn the track as we would know half of it allready ??
edit 2 : there is also a SHENANDOAH CIRCUIT not sure if i have ever done it but it looks interesting on paper. Dont think this version is Ac.