If they come in a box I assume that they are in powder form. The Stevia most likely contains maltodextrin. In fact, MOST of the powder in those packets is maltodextrin. Do a google search to find out what it is. As to the Truvia, I can save you the trouble.
The Truth on Truvia – Dietitian Cassie
I've used "pure" powdered stevia in my tea for many years and love it. When I started DIY I purchased a bottle of pure liquid stevia (KAL brand for both the liquid and powder) to put in some of my mixes. First, It doesn't take much to make it very sweet. I would start at no more than 1 drop per 10ml. Second, I hope you know how to rebuild coils because you will be going through a lot of them. I have one mix that I added 1 drop per 5ml of
juice and I have to change coils after
vaping about 5-6mls. Granted, the mix itself contained mostly sweet juices to begin with (caramel candy, English toffee, etc.) but adding the stevia most certainly sped up the gunking process. I also use cotton wick which seems to gunk up quicker than silica.
Don't get me wrong, I'm not trying to talk you out of using stevia. I just wanted you to be aware of a few things.