Low rider racks can and are attached to forks with clamping hardware around the fork blades all the time, no need for specific bosses. But a disk brake will steal space so some mods of disk specific rack will likely be needed. I strongly suggest you consider a front pannier system. In fact many minimize rear panniers and shift as much weight to the front. This is but one aspect of gaining your own experience. You can't find your preference on line.


I was told by a inside the industry guy years ago that only some areas of CA and upstate NY (as in the Finger Lakes) were bemoaning the loss of triple cranks from the new bike specs. That and the inability for many riders to learn how to shift properly combine to make wide range doubles the WAY. So then it's left up to the marketing departments to make this WAY the one that buyers will take as being the better WAY. I take this attitude as a load of BS and sad that we older riders who learned to shift properly decades ago end up being slighted.


As to shimmy at speed- The differences between your two bikes is FAR more then just the handle bar/seat relationship. Please don't see a difference and stop your discovery at that one difference. Shimmy is still a very miss understood effect and it involves a vast number of elements including the rider themselves.


Years ago I read of an older couple that was planning to tour the world on their tandem. She died before the trip and he decided to do the tour on the tandem anyway. He fabbed a rack which straddled the stoker's top tube, effectively ending up with the weight well ahead of the rear axle. I always thought this was a great idea. But note that I haven't built a bike like that (and there's no reason why I couldn't do so but personal choice).


So I'll return to my question for you: have you toured yet? Yes, I know that you answered already but the actual exposure/discovery of what you need in a camping load, in a loaded bike is yet to be really known. I've self contained a few thousand miles since 1973 (and supported toured more as well). I've had a half dozen bikes equipped as tourers (4 of my own making) and my find with each bike a further understanding of what I want and what I will do differently next time. Most of the evolution is of rather small differences but spending hours on a bike day after day those small details add up to major pluses. There's no way my current touring bikes could have been designed (by me) the way that they are back in 1978 when I first started to make frames and my touring grew more frequent. So I strongly suggest that you do what you think now is the right way but understand that with keeping your eyes open you will view you choices as not quite the way after you gain actual touring experiences.


I hope you have a lot of fun in both the touring as well as the thinking. Andy.