Another alternative came to mind if I'm making a permanent modifcation anyway... why not lop off the crude saddle completely and weld a flat plat right onto the tube? But, I'm a little concerned about the integrity of the plate-to-tube weld. If there was any imbalanced load it might pop off one side (not trusting my welding skills here).
Then a (short-lived) Eureka moment... how about making a detachable flat-top to go on the bottom of the tube, and flip it upside down? See photo.
That way I can leave the saddle intact, and make a more easily constructed removable flat-top (a plate of steel with a block welded on the bottom that inserts inside the tube).
But, as you can see from the photo, the problem is that when you insert it upside-down, the saddle prevents you from adjusting it any higher than shown on the left. As opposed to the normal full-extension as shown on the right.
So, I think I'm back to welding a plate on top of the saddle. Seems like the easiest and the safest... my weld is really just holding the plate steady, it's not under any load.
The disadvantage is obviously that the stand is permanently modified... if I ever wanted to use it as a saddle-type I'm outta luck. But since the stand is so cheap that's only a $20 fix... just buy another set.
1999 E320 Wagon