Welcome to the forum and to glider parenthood.
If you are feeding HPW you are not limited to the frozen mixed vegetables to go with it.
You might try offering broccoli, spinach, sugar snap peas, green beans, okra, cucumber or any other fresh or frozen vegetable you want to try. Offer a wide variety and see what your gliders' favorites are.
The only vegetables that should never be offered are onions, leeks, garlic and rhubarb. Gliders should also never be offered anything containing Chocolate or artificial sweeteners.