First, I'm surprised they're working well at 70-80W in a Recurve. Not the smallest single coil atty out there but still not all that big. Even with higher mass complex coils I rarely exceed 50 W, but you may very well prefer a warmer vape than me.
Battery safety us an important topic in vaping. With a built in battery you're relying on the manufacturer to have installed one with the proper rating. With the Pulse arriving, it's your headache. While it is a regulated mod which adds a degree of safety thanks to built in circuit protections, running it at 70-80W is best done with a 30A rated battery, 18650, 20700, or 21700. The size affects total charge as in mAh, which gives you a feel for how long it will run. The true CDR rating tells you how many amps it will safely provide without getting too hot or doing bad things. If you are commited to 18650s in it, then a Samsung 20S will provide 30A and 2000 mAh of capacity. Sorry this isn't the latest rating chart by Mooch (I know bad me. I'll update this evening) but here's a list of both batteries and at the bottom trusted vendors. While it is out of date the ratings on the batteries shown hasn't changed although some newer 20700 and 21700 should be on there
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Regardless with the latest ratings the 20S would be the winner if you only use 18650s.
(Mooch I promise not to do that again. I'm running late and can't find a newer one in my photos on the phone. Honest)
Edit: this is the latest. There should be another one coming out in May
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