its very very risky getting that base, you can die, your family and some part of town, soo... i think will be better if you stay in safer side.
If handled properly, there's no true risk associated with handling and using 72mg/ml nicotine or even 100mg/ml. It's all in how you handle it. Wear gloves, keep exposure to a minimum and clean up after yourself. As long as you're not shaking an open bottle or slinging it everywhere, you're fine.
We're talking about mixing it here, not drinking it

(which, of course, is
definitely not recommended)
As for the OP, IIRC, 75mg/ml is the maximum. You may want to check out NicVape to see if the pricing there is suitable. I've spoken to quite a few from the UK that have ordered from them and they offer 75mg/ml, so you can get exactly what you need.
Unflavored Nicotine Liquid || NicVape