I have heard that weed from the 70s era only had ~2% THC where now at least dispensary grade can hit 20% to 25% THC. That could well be due to the drug war selecting for more powerful highs in smaller packages, but i would think that would also reduce the quantity needed to get the high you want.
Put getting a good dry herb vape to the top of your priority list it will save you money in the long run bud last so much longer and smoke is so much cleaner its unreal. If only I had a time machine and tell my younger self.
This year properly starting the dry herb journey I started went with the arizer air max and would recommend it to others. If you are patient can get it on sale from arizers website probably around 4/20. Pair it with the extremely long stem with a carb that sneaky pete vaporizers makes and its an almost perfect portable vape.
Other one I would recommend is dynavap m+ which heats with torch or induction heater. I got the dynavap for myself as a Christmas present after 6 months of the air max as my sole daily driver and man its a completely different experience. Fucking around with a torch is annoying and you can easily over do it and combust the material but it extracts herb so quickly and efficiently in one go that .1g will produce a heavy hitting cloud of milk its insane. Only issue with dynavap is you will get tired o fucking around with torch and look into induction heaters only for the outrageous prices to kneecap you.
Good luck with whatever you do in your cannabis journey ;)