When you cut off that pin, you just gain one more leaned-back position (like in those pics), you do not gain anything inbetween. So you have the normal position, then the one in those pictures.
The stuff MOT sells I believe are fully adjustable all the way back, different than just cutting the pin and letting it go back quite a way.
We all did this in a big Cruiser party one Sunday (probably those previous threads that I was too lazy to click on), it was cool, but I can't say I ever used the leaned-back mode on those seats, it was too far back to be comfortable IMO, maybe for sleeping, not sure. It's not easy to modify your existing brackets to do the incremental leaned-back modes, it would require cutting many notching in a ring at very precise intervals (when the seat latches there are 2-3 teeth that all engage together, so if you want to make another position for it to go into you have to cut in 2-3 grooves at just the right spacing/profile so the teeth engage good and are solid) much harder than just cutting one groove to give it something to catch on.
Good Luck...