So, I did a few tests. I made 20 gram candles in little glass tealight holders. I made one out of the partially hydrogenated soy wax, one fully hydrogenated, and one that was 12g fully hydrogenated soy wax blended with 8g coconut oil (76 degree melt). They all had more or less perfect tops, except the coconut blend. That one was matte on top and just a little lumpy but not too bad.
And then I did another round, but added 2g lavender EO to 20g of wax. I also didn't do the coconut blend that round, but used my usual GW464 just to compare.
Oh my goodness. The fully hydrogenated soy wax was the worst when I made it with the EO. I got strange crystals like the pink candle in the OP.
Here are the pictures:
This first picture is, left to right: GW 415 (Partially hydrogenated, basically 464 without additives), fully hydrogenated, and then the fully hydrogenated/coconut oil blend. The fully hydrogenated one did not adhere to the glass at all. It popped right out and was very slick and shiny, and very hard. It also shrank a lot more than the others.
This next one is 20g of GW464 with 2g lavender EO. I have no idea what made the "scratches" on the top, I've never seen that before. But the top is level without any weird bumps or crystals.
This next one is 20g of fully hydrogenated wax with 2g lavender EO. I am going to make a few more like this and take a timelapse video of them cooling. I think that would be interesting.
Next is GW415 with lavender EO. This one looks fine.
I have not test burned any of these to check the hot throw. In my experience, hot throw is hard to test in a candle with such a small surface area. However, I will burn them just to see how they burn, and how they resolidify after burning.