From what I have done, whether or not you fill the hole is inconsequential, just make sure you have a good joint. If that fills the hole then ok, if not ok, IMHO.
Having soldered literally since I had to stand on a chair to reach the bench, and being taught by a radiator man who unsoldered and resoldered automotive radiator tanks, even so far as unsoldering the thin copper and brass tubes from the header that the tank attaches to, all with an oxy/acetylene torch, (that's temp control!), I think I could call that training and experience as well, at 51 yrs old. I am certainly of the school that only pokes the wire into the hole and support the part well enough to see that it remains steady till the solder hardens. (An alligator clip is handy for this, when needed, and also acts as a heat sink between the solder joint and the body of the component.) It is much easier, quicker, and disassembly is MUCH easier. That type of electrical connection is plenty good for the currents flowing through these amps.
The only way I even attempt to make a mechanical connection first is if the amp (current) load would be enough to heat the connection enough to melt the solder, like on auto battery cable ends and such. These have sometimes 400+ amps and a poor connection can melt solder right off the joint. In an amp, most connections are milliamps, not enough to heat a hair size wire. (Maybe a little exaggeration, but not much.) A sound joint that won't cause a whisper of noise when wiggled is plenty good.
Regards Ya'll,
Jim