Many people have H&T SYE's and have no issues.
Right...i think vibes, that are caused by the yoke itself, are only an issue if the outputshaft and the yoke are cut off too short. Having too less spline-length, you get too much play in there, that causes the vibrations. Actually the yoke does look pretty short on Porch's pictures! Looks similar to when i had it on my Jeep.
Nevertheless, you should get that pinion angle right! Just to be sure, it wouldn't be bad to check the front driveshaft, by driving without it, too.
If it's not too expensive let the rear ds be checked for balance...maybe it's not the main problem, but causes part of the vibes too!? Driving without the rear ds won't get you any smarter...in any case the vibes are gone...but if the yoke itself is the problem, the vibes are only gone, because there is no more weight tearing on it, while the ds is not installed. Same goes for the pinion yoke.
Welding the yoke to the shaft should solve the problem. But you won't be able to open your Transfercase anymore! (Well at least not without grinding down the weld before) Keeping in mind, that you already "killed" your output shaft, and the only possibility (if welding doesn't work) is a "real" SYE, that includes a hole new shaft.....why not try it !? At least it can't get any worse!
