How to adjust the gap of the prime tower hollow section?

Excessively large gaps result in poor top surface finish.
I cannot find any parameter to reduce this gap.

This is probably a stupid question since I do not use any kind of AMS, but…
Why does the surface finish of a prime tower matter? Isn’t it just waste material?

Since I’m being stupid…
Why build a tower anyway? Wouldn’t a purge down the poop chute and a quick wipe be as effective and quicker?

It collides with the nozzle, which may damage the nozzle and the printer’s XY structure over time.

This also makes the prime tower ineffective for priming and leaves excess filament stuck to the nozzle.

The prime tower stabilizes filament pressure inside the nozzle. Without it, the initial extrusion of a new nozzle will always turn out poorly.