I would just ask herb man he says he likes them a lot i think he uses the calmag as well if not i know for sure GTD and possibly donny do. you should pm those guys they will probably be the best for giving you the follow up you are looking for.
Good stuff! I started using metas last year on Herbs recommendation and love 'em...They work especially well in my vege garden. The soil I use w/ amendments for the kind bud don't seem to need much help...