Personally, I don’t think people should new a new restrictor gate unless they’re absolutely hopelessly uncoordinated and can’t get used to the LS-32 as-is (aside from spring tensioning and that’s not a huge deal to change).
The LS-32 is far easier to come to grips with squaregate-wise than the JLF is… The levered microswitches, if anything, make circular AND diagonal movements easier on the LS-32 and other Seimitsu joysticks. The levers are also part of the reason why the LS-32 engages faster than the JLF.
Seimitsu did make a circular restrictor gate for the LS-32. It was a white plastic part you had to buy separately. $3. Akihabarashop.jp and most other vendors don’t stock the part any more but a few other places still have them. I am unsure whether Seimitsu makes this part anymore but the fact that Akihabarashop.jp hasn’t listed it on its website in over a year should probably be a clue since Aki-shop generally carries most, if not all, the available Seimitsu catalog. I used to use the circle gate on the LS-32 but abandoned it when I realized it got in the way of playing with fighting games and frankly wasn’t that useful. (Still have two LS-32 circle gates I was unable to sell awhile back. Didn’t throw them away. You just never know…) I like this new subguide design even less than the circle gate. Pass.
For anybody worrying about replacing the original LS-32 C-clip with an E-clip and the E-clip impacting the subguide, don’t worry. It’s never been an issue in the 4 years or so I’ve used LS-32’s. I’ve modded all of mine with 3/8" E-clips and they don’t affect operation at all. The E-clips don’t hit the gates.
As far as I can see, the only way an Octogate could be useful in an LS-32 is to remove both the subguide AND main guide from the stick base. Then, screw in the octogate. That’s the way the old circle gate was used, too. Otherwise, you’re going to have the same “knocking/long-side” issue the newer subguide will inevitably have.
The LS-32 isn’t the LS-56 and it shouldn’t be necessary to futz with the restrictor gates and get a replacement part unless you can’t come to grips with the basic switch design. I wouldn’t even touch the LS-40 gate and that’s one of the looser Seimitsu joysticks, too.