Hi and welcome from just over the border in Buffalo, NY. I have a non joytech ego c. I think you'll be fine with most juices with the joytech from what ive read on it. Being that it is a tank system you may find that juices which are high in VG content, or just too thick, might not wick well enough and need to be thinned with a tiny bit of distilled water. You'll get nasty burned dry hits if thats the case. I vape all vg juices because im pretty sensitive to pg.
As far as buying juices many people like Johnson Creek although Ive never ordered from them. Some of their juices are used in blu cigs. I didnt like them. When you buy it online the supplier should have listed on their site the nic content, vg/pg ratios, etc. If your question is along the lines of "how do i know what mg level is right for me?" its kind of trial and error. i smoked 35 light cigs a day for almost 25 years and at the start 24mg was too much for me. So 16-18mg set in fine, but its jndividual.
There is a ton of info in these forums. A goldmine of it but Id start with the stickied threads and spend a good amount of time educating yourself. Read, write down questions, and invariably as you read more those questions will get answered. If not, post them but i betcha most of them are already here someplace.
stick to it.
