The effectiveness of any muskrat float depends on its proper floatation and balance. You may want to consider looking at the design and material options in these examples of floats that other trappers use.
This is a condensed version of a post that I made on Trapperman a couple of years ago for your reference:
Muskrat Floats: An Overview There should be a style among them that would be suitable for your needs in terms of expense, availability of materials and ease of construction. Keep in mind that the multiple-catch, floating "colony" traps shown are not legal in New York State.
Good luck with your new adventure.
Jonathan