Hey man that sounds great for your first flute, the flue is always the booger in building these and instead of messing that one up by toying with it to much I would leave it. I think you did an excellent job and if that is your first one then you will surpass what I'm making in no time. Glad to see you were able to muck your way through my build along and get one sounding this good. I think after looking at the flute, even though you probably used my measurements, that the holes look a bit to low on the flute and may be a bit to close together, that might be causing your holes to be smaller at the bottom.