Yes, a picture would help us alot.
And the cornstarch test may not work if there is a styrofoam layer between the top of the fridge and the plastic part.
Expensive regulators are servicable i.e: Parts are available to make repairs and have better quality standards. Cheap ones have to be replace alltogether if they are defective and may not all hold pressure steadily.
A High pressure gauge is always a good thing to have and not a big expense over...
Just a quick question.
What do you mean "The capper doesnt seem to reliabily cap the bottles." ?
Do you mean that it can be unscrewed off an empty bottle easily or that your tried carbing and it won't hold carbonation?
Because it's normal that caps are easily remove from a none pressurized...