Do not use VG at all. It won’t meld with the concentrate. I am currently using rosin and pure PG. Just heat the PG to about 140-160 degrees F in a double boiler (pan of water with a shot glass in it works too) and let the concentrate melt for a few minutes. Then stir it until it’s uniform and then inject into your carts. I use CCELL brand carts (not knock offs those tend to leak) and have had great results. I use a 1:1 ratio for the best results. This means 1ml of PG to 1 gram of concentrate. If the concentrate does not melt then something is wrong with the concentrate. I have a rosin press that uses pressure and heat to extract the resin and it works great for eliquid suspension.
The article I read must of suggested pg, not vg, just didn't remember right. But, they mentioned that it still separates even after its blended when warm, and that there was still issues. Could of been an older article too. As I'm retired, live alone, and rarely travel, I really have no reason to pursue it. I also have a heat press, I been pressing at 120 and 100 micron but have 75 on order. You get almost as much oil, as using say a 220 vs. 100 microns if you prepare it well. I use a dab rig, have a reclaimer on there. And, if I do go somewhere, I have a Yocan torch. Hope you get the OP going and glad you have luck with the vape pen. :cool: