Hokay, so...
There once was a time when amps didn't matter on regulated devices, but with all the newer ones (within the last year or so) promising 200+ watts, it can matter if you're planning on pushing your limits. As
@nightshard said, you're not going to be able to go much above 120 watts with 20 amp batteries. And there's no such thing as a 35 amp cell - if you're lucky you have 20 amp cells with a 35 amp fake wrapper, if not they could be cells rated as low as 8 amp. I don't like fake battery wrappers, and there's no reason to buy from them when legit companies (Samsung, LG, Sony) sell cheaper than the bogus brands (Efest, MXJO, etc.).
Also, both of your batteries will take a full charge of 4.2 volts. They'll quickly drop off, though, and spend most of their operating life at 3.7 volts, when they drop below this it's time to change them out for a fresh set charged to 4.2.
There's a huge difference between real batteries and fake batteries - the real ones are safe when used within spec, the fake ones are PROBABLY safe if you pretend they're rated for 20 amp instead of whatever they claim.