You don't need to test ride to know when a head tube is going to be too short on an LHT in the frame size that has the Effective TT your cockpit needs. Take a measuring tape to the bikes you already own and see what geometry fits and then use those number against the published geo charts from surly and jamis (but you already knew this, right?)

Personally, I got a pro bike fitting and found out my numbers and used those to evaluate some how close the stock geometry of certain bikes comes to my ideal fit. For me, the LHT's short headtube would have meant way too may spacers under the stem in the frame-size which got me the right horizontal TT length.

Aurora's, on the other hand, had much better geometry for me. So, I know they're dramatically different and this is the kind of bike you're going to be spending Loooooong days in the saddle. Forget about the minor spec differences - you can fix those, but focus on the frame geometry suitability cause that can't be fixed (and don't tell me you can just swap out the stem....or we'll really side track this thread).