Most concentrated thc infused cooking oil possible

I have been baking cannabis edibles by heating 6g of good quality buds in 250 mL of oil at 98C (pot placed in boiling water) for 4 to 6 hours. That has worked well for me, but I was wondering how much more concentrated can I make my product (ie how much high quality bud can I cook in a volume of oil and still have most of it disolved by the end of the process).

Also, does anyone know how far can I go with glycerol?

Edit: sorry, I've missed this topic: http://rollitup.org/t/maximum-potency-minimum-oil.823329/
Moderators, pelease delete.