Not a medical advice just my personal experience.
I started with 50/50 PG and 12 mg nic. I was experiencing a lot of cough and "tender lungs" , switched to VG only and
aside of a some phlegm all my other problems pretty much went away.
Make my own juices but when I vape already made
juice I chose highest concentration of VG and works for me because I found Pg irritating my throat and lungs.
Regarding the higher ohm... depends on what you use for battery, if you have a variable voltage
device it's won't make much of a difference
because you can adapt the voltage to whatever resistance you have on. There is a graph around ECF showing you what to set for each resistance use that for guidance and tweak based on taste of vapor you get.
Hope it helps