I had to replace the hydraulic pump in my 2N. When faced with the gymnastics associated with having to pull out on the touch control linkage from both side covers, at the same time...There has got to be a better way to do this. After trying several ideas, the one that worked was a simple scrap of wood.

The scrap was cut to 0.375" x 0.75" x 3.75" and wedged between the two linkage arms with one hand, working through the right inspection hole, with the touch control lever in the full DOWN position. With the wooden wedge in place, I could then reach under the tractor and tickle the valve link loose while still looking thru the side inspection hole. Piece of cake and I never had to remove the other inspection cover.

Once the rebuilt pump was in place, I put the valve links at the pockets on each leg of the linkage and carefully pulled the wedge out. Done, on the first try!

The little wooden wedge is now labeled "9N TC Tool" and hanging on the wall with some of my other special tools.

Your tool is a little more precise than what I used but the same principle. Growing up having to create my own 3rd hand at times, it was a piece of cake. Nice job of posting.