Question 3 - Yes, the rubber sleeve acts as a stop against the centre seam on the bottom of the exhaust pipe on GTR. I'm pretty sure they used the same stand on the GTR and GTO.
Although this toe piece looks simple, getting the angles right is not quite straightforward. Best advise I can give is that when the stand is raised the outer sraight end has a slight uptilt from being horizontal to the ground. Its vertical centre line is at 90 degs to the exhaust centre line.
I would make the primary bend first (angle?), leaving the outer end long. Then weld the piece to the sidestand, tilting the outer end forward as picture 4. Then fit the stand and adjust the outer end to my advise above, put the up curve on the tip and cut to length. But then again, I'm pedantic, lol.