I don't use the specific version of Testors you're talking about. I use this:
The main difference is the metal stem instead of the plastic one. It allows a smoother flow of glue and can be degunked by using the wires they include (unlike
GW). The benefit over
GW's version (aside from having wires) is that Testors' is cheaper per oz and you get more in the bottle. I have never had an issue with this product.
Here's the trick to using it. Never use a lot. Cover the parts to be glued with as thin a layer as possible, using your fingertip to spread it out as needed. This prevents glue from spilling out between the joins and also allows better fusing of the plastic into a single piece. If you wind up with a little extra glue, just use a damp paper towel to clean it up before it has a chance to work and your model should be fine.