Direforge has been my go-to mod for DF for a long time, so I'm always happy to help. This is the first time I've played the Shyhak in depth, though. Having a lot of fun mass producing fine shyhak wax and building buildings out of it.
Holy wax is a lot trickier - even appropriate Good biomes only rarely have valley herb.
EDIT: Honest question, what's the point of converting holy wax and clay into kaolinite? Porcelain's nice, but it's mat value 10, the same as fine wax... and you can make most of the same objects out of either. It can be glazed, but so can shining marble, so if you have flux stone and a legendary glazer hanging around, shining marble's the better option, and that's assuming that glazing is going to make up for losing 20 points of mat value. I'm not sure if holy wax is too valuable (considering making it IS rather difficult) or porcelain's just... unimpressive with all the shyhak'ur wax options, but I feel like I'd rarely want to trade holy wax for kaolinite. I guess porcelain is more resource-efficient for pots and furniture than wax, if you have limited amounts of wax or limited labor to refine fine wax - but if you've got holy wax you're obviously producing a pretty good stockpile of fine wax.