Lou, you may very well in good enough shape to do this.
But I (and the others?) think alot of people mis-interpret how you are supposed to be doing 'HIIT' and/or 'Tabata'.
I (we?) don't think many others realize what max effort is. . . .or how shitty a TRUE Tabata workout is supposed to be.
I do my prowler 20 sec full hard max sprint w/ 200# of weight . . .then complete rest 1:40.
I can't imagine doing 20 sec ON / 10 sec OFF for 4 minutes . . .not at that intensity.
Either you'd have to start striping load off ea round (which might be OK I guess)
. . . .OR, your "sprints" would look like "dead-man walking" in four rounds . . . which I think, may not be really optimal.
Alot of people are just doing "Intervals" and calling it HIIT or Tabata.