For the juice you already have, if the flavor is strong enough you can try cutting it a little by yourself. Get a bottle of "Glycerin USP" from a local drug store -- Rite Aid, Walgreen, Walmart, CVS -- it must say "Glycerin USP" and it will likely say "Skin Protectant". The ONLY thing in the Ingredients should be glycerin 99.5% (or higher), with possibly the word "(anhydrous)". It is typically found near where they have the isopropyl alcohol, bandages area -- a clerk at the pharmacy desk should be able to find it quickly, just say you are looking for Glycerin USP. About $4.50 for a 6 ounce bottle.
Use about 2 drops of this VG with 8 drops of your existing juice in a separate, small bottle, shake it up. The result will be lower nicotine and higher VG (lower PG), though with a bit of loss of flavor. It will cut your 24 mg juice to about 19 mg, with the VG jacking up the vapor a bit.
(VG is actually much thicker than your e-liquid, so you might try first with 1 drop -- the VG drop is likely going to be much larger than a drop of your liquid.)
Otherwise you can do a similar thing with regular distilled water, from a supermarket -- $1 for a gallon, buy the stuff that says distilled on the label. Unfortunately this will thin the juice a fair amount, and won't give you the nice bump in vapor that VG does, but you will still get a decent cut in nicotine level.
