for now I use somewhat of a look up table where I look at the ratio of helical height change to arc length. Using that ratio I decide on a proportional feed rate multiplier. I am still using G9 / G8 a lot too. With this table the booming is pretty much gone and I can run fast feeds on looser helical paths. Also, any helix below 0.002" radius gets made into lines.

Additionally I bolted the machine to the concrete and that helps a lot with the noise and vibration.

rigid tapping works good too