I can't speak about Maxx Fussion mini carts because I've never used them, but... 24 seems high, maybe in liquid form for DIY mixing. I vape 18mg/ml ejuice from Halo, and I find myself getting too much nicotine. Then again I was never more than a .75 PAD smoker, and that was some time ago. Prior to switching to
vaping I was only smoking occasionally, mostly when drinking, down from about 2 cigs a day a couple years ago and a previous 1/2 PAD habit that lasted about 10 years. I don't think starting low is necessary, at least not real low like 10 or 6. I'm planning on dropping down to 12 the next time I order ejuice, and may end up at 6 eventually. I like to vape a lot, but don't need as much nic. as I'm currently getting. I do think 24 would make me puke.
Newports have 1.2 mg of nicotine. So at 30 a day you'd be getting 36 mg. 24 mg carts would give you 36m a day if you vaped 1.5 ml (assuming my calculations are correct) - that's roughly 30 drops (or TWO CARTRIDGES) a day. It just depends on how much you vape, and assuming the prefilled carts last as long as they should. You could get 36mg of nicotine a day with the 6 mg/ml cartridges, if you vape often enough - but you'll go through more cartridges that way.
Of course I'd recommend direct dripping or using re-fillable blank cartridges, rather than pre-filled carts - but that is just my preference.
I think menthol is best, but that's also just preference. I also like to try other flavors, which is why I recommend direct dripping and/or refillable carts. That way you can also experiment with different nicotine levels.
It is a bit less convenient than prefilled carts, but not so much as to make it a hobby. If you fill your own carts, you can always top them off. I've found that prefilled carts and cartomizers don't always last as long as they should and you end up tossing them out early, but they do make for the most convenient and most analog like experience.