If you change her diet too drastically and too quickly you may make her sick. Be careful of this. Watch for changes in her droppings, and the ability to pass waste, both solid and liquid. Her stomach may no longer be able to handle some foods, even if they are good for her... and you may have to work with vitamin supplements for some things.
Super worms are full of protein, and if she is not used to a protein rich diet, this could make her very sick very quick, and lead to other long term problems. Go easy on the worms... use them as only a part of her diet, along with all the other healthy food options and a few of the foods she is used to. Variety is your key to healthy. As the saying goes, too much of a good thing can be no good.
As for burrowing worms, if you don't find them they will form cocoons and hatch into moths, which will lay more eggs, etc. They can be a big nuisance and hard to get rid of if allowed to escape the enclosure. My suggestion is simply to change the bedding if that should happen, and be sure to find the worm while doing so. There is never an inappropriate time to offer fresh bedding to a turtle. A dirty turtle can cause salmonella issues... and while it tends to be more concern in aquatic species, that tends to be because water makes it easier to spread disease. All turtles carry that risk.
When it comes to feeding the worms, if she's happy with a tweezers and its low stress, keep doing what works. That is time for you to bond with her, thats always a good thing too.