Rutgerson grommets are one of the most common brand of grommets used by sailmakers for reinforcing the reefing clew/tack cringles. If your sail doesn't have Rutgerson grommets, it is a relatively simple matter for a sailmaker to replace them. The loft I had install my third reef used them for the third reef and retrofit them for the other reefing points so that the blocks could be used on my sail.
Hm, in my case, I installed the grommets for the third reef myself. I don't think I paid attention to the brand of the grommets. Given that they size them in millimeters (25mm or 35mm), I wonder if they are metric.