Fipple Design for Homemade Whistles

I am in the process of trying to make my own whistles, as if 14 different commercially made one were not enough, and I have been following the “Comprehensive Guide to Building Tin Whistles”. My first attempt I tried to made two fipples at the same time just in case one turned out bad. I was right, one turned out very good and one turned out bad yet they seem almost identical in construction.

Even though I am very satisfied with the good fipple, does anyone know of alternative designs that may produce a flatter windsheet?

Was a 50% success in making a fipple good, bad or just about right?

You might design the windway to taper from tall at the mouth and narrow as it reaches the exit of the windway (sort of spike shaped). I like this style as it reduces clogging and gives a good full sound.