[Artjom Ross]

We've consulted Oberon Performance and they've advised that their design is to work with an OEM setup. Therefore, if your master cylinder is activating an OEM slave without issue, then they can't imagine their design not working also. At least, no one has ever reported it to date over the years.
For their added part, they are familiar with other types of slave that have much bigger piston sizes, and if the Factory Racing one has a 31mm piston then yes not enough fluid is moved by the master cylinder - causing such issues. The Oberon design has a 29mm size piston, which will require less fluid than one that has a 31mm piston. This is the best we way we can answer this inquiry.
Это ответил мне продавец Oberon продукции, особенно интересен второй абзац, в целом всё стало яснее