So I’ll be fine using 2 of .39 coils and yeah im going to use ohm reader first
No,
2 coils that measure .39 each will result in .195 when installed in your rda.
4.2v / .195 = 90.4w and 21.5a battery draw.
You've said you're using 15a CDR cells, 21.5a is pushing those way too hard, especially for someone new to mechanical/ rda use.