You can give it a try but I would use 100% PG and a four week soak for a cold maceration. Your going to use your extract like a DIY flavor concentrate. Figuring out your other additives will be a lot easier with the 100% PG.
If you still want to go with the 75/25 VG/PG 12 mg. solvent, you might want to follow through in your thinking to the end result. You end up with an already mixed concentrate. How are you going to dilute it? You've got a super-strong already mixed concentrate that needs dilution.
I know you want to say, " But it's already mixed " and I say, " Yes, but it's still concentrated, how are you going to tame it down? "
After 80+ NET maceration's under my belt I've learned, nothing beats time for good flavor. You can use all the heat, alcohol, etc. but a long soak in PG will get you good flavor every time. That is, if it's there to begin with.