John,
This line in your post concerns me and I want to help:
I am worried about fit but will have to dial it in on my own but these seem to come somewhat dialed in. For roughly a year I've been stewing on the issue of.....how does one sell the appropriate super bike on-line? Or from your perspective...how does one buy the appropriate super bike on-line? The first/easiest step is this: if you're comfortable on your current bike? And if you feel powerful in your current position? and if you think that position is a good starting place then here's what you and all new bike buyers in your situation should do.....
Get you bike level - it would be best in a trainer with something under the front wheel but you could simply lean it up against the wall as close to vertical as you can without it falling over, and with the front wheel straight.
Measure your Pad Y & Pad X - this is best done with a laser level and the cross-hairs right in the center of your bottom bracket (bb) but it can be done manually if you are really diligent about accuracy. Get a friend/family member to hold a long level right across the bb and then measure up to the top of your arm pad (Pad Y). Then turn the level vertical - and again right through the center of the bb (this could be done with a plumb line too) and measure to the rear of the arm pad (Pad Xr) and to the middle of the arm pad (Pad Xc).
The idea here is this - you're current bike fits pretty well, so we're gonna take the Pad Y/X off of it and compare it to the bikes you're considering. We can look at each new bike and see 1) if that bike has the same characteristics, 2) what size in that bike, and 3) what tid-bits (stems, arm pad spacers, etc) of hardware on needed to get the pads to the spot you like.
Lot's of "ifs" in this post. If you want to duplicate your current position and if you can measure it then come back to this post and together we can locate and reach the Pad Y/X prescribers of each bike you're looking at to pick the right one.
Ian
PS. let me be clear.....this is NOT the best way to prescribe a new bike purchase. The BEST way is to go to an
educated,
experienced fitter in your area who - and this is critical too - has the
proper tooling (dynamic fit bike) and do a brand new fit from scratch. Out of that fit will come your perfect Pad Y/X ('cuase there might be a better position than your current bike) as well as all of your fit coordinates (seat height, set back, cockpit length, and all the details that lead to perfection). You might pay $250-$300 for that fit but you'll come out the other side absolutely certain of what bike to buy, knowing what parts you need where to make it perfect, and all of your fit details to be at your best. You've had your current bike for over 10 years. I think your new bike might last that long too. I think $30/year is worth comfort, power, happiness.
Ian Murray
http://www.TriathlonTrainingSeries.com I like the pursuit of mastery
Twitter - @TriCoachIan