[slijin]

There is no rule that explicitly requires you to install a fan on motor controllers. The only rules mentioning fans are R32 and R65, which simply permit the usage of such fans. Nevertheless, you should still raise this question on the Q&A.

Do, however, keep in mind that the Victors are designed to operate with the fans they ship with, not without. Talons are arguably more robust in this respect, as they are designed with a heat sink and the usage of a fan is, in comparison, only "recommended". As Victors are generally used with fans and Talons are being introduced for the first time this year, there is no reliable precedent for doing what you propose.

Something to consider if it really is that much of a problem would be to use the 10mm fans (as opposed to the 20mm that the Victors come with), and then trim down the securing pins (in the case of the Victors) and use some manner of adhesive to secure them. If you do use this option, however, be sure to first pose this to the Q&A as well, as modifying motor controllers for mounting purposes is not explicitly discussed in the manual.