I say the Lishen LR2170SF is the best 21700 cell for the PL47 regardless of emitter option. It is a 15A cell and anything higher current will not make much difference in a quad. The capacity is not too far from LG M50 and Samsung 50E but it is much higher current and the superior discharge curve ensures better performance as the battery drains.
Edit, come to think about it for the 219b version, don’t think you should use the LR2170SF. Might be pushing the 219B too hard. SST-20 version should be fine though. For 219B, either the LG M50 or 50E is safer.