I'm intending to use it in low current projects like oscillators, arduino projects - these sort of things - to learn electronic but also I'd love to drive fly-backs for juicier arks (which I've already done with my ATX power supply, of course with the standard measurements and personal protection to avoid electric shock), and olds vacuum tubes. I could instead buy one here. But, for a reasonable price, I could only find Yaxun brand, which I don't take a lot of faith (the good one are like 3 or 4 times the price of these Chinese).
I do not think I'll draw too much current from it often... So, this point can be left aside, but, yeah, you're right: by mine calculations, something about 7W per transistor will be lost upon high load.
The first question is crucial for my project!
Thank you for your reply!