If you were to try either, which also have back supports, you will appreciate the superb seats. I did change the rear shocks for some Triumph softer ones a few years ago. The Thunderbird has much better suspension than the R111 though. I was lucky these bikes were available to allow me more riding on modern bikes. I found i could just about work the gears on the new 1200 T120 but not on the 900 version with a lower seat.
Worth considering footboards if both your feet have been smashed up.
Old bike looks funny as i hit the rear brake with my heel.