Check out juvederm, it is low molecular weight, and it is available up to 30mg/ml. I have been reading so much on this stuff, and some of it is way above my pay grade. I will have to send you some of the info i have found, because from some of my research it seems to indicate that the low molecular weight lasts longer. Most of the information is for topical skin products or dermal fillers, not as much info or studies for use in muscles.
Let me know how it goes when you make your first batch. I was thinking about trying the hydronics, but after researching it i think i may just go with mediphorm.