The ULT isn't recommended for use in a classic valve due to the reduced return force on the top of the on-off top because of the regulated air pressure. The ULT also isn't recommended for use in a pneumag setup because it doesn't provide enough return force to properly reset the pneumatics. A pneumag setup requires the on-off to push back both the sear and the pneumatics, so it needs more return force than a normal sear setup.
The ULT will fit in a classic valve. It is a drop in replacement for the on-off assembly. Only use the orings that come with the ULT. If you install too many shims, it could go full auto.
Except for the Automag in front, its usually the man behind the equipment that counts.