Hi daniloperusina,
Actually, I do keep a tuning lever on hand to take the curse off a note here or there between tunings. I have tuned pianos before, usually as a favor to friends who have less expensive, old pianos where I can't do much harm. But I prefer to have my own piano done by the tuner.
I had an interesting experience though a couple of months ago. While the new strings were stretching on my Baldwin, one note in the high treble slipped. When I attempted to turn the pin (the new pins one size larger are TIGHT), the metal alloy (a cheap tuning lever) in a nanosecond shattered! The sudden release of torque threw my hand against the plate, but I wasn't hurt, and was just glad that a fragment hadn't flown up into an eye. I recovered one large fragment quickly, but the other one eluded me. Then, after making the Bortkiewicz recording I posted here (on page 2 now), I heard an odd "ping" sound on the recording. Having perfect pitch, I knew right where to look on the scale, but at first detected nothing. Then with a high intensity lamp, I saw a recessed area underneath a plate strut, and there was the elusive fragment lying on top of the waste string of the note I suspected. I got tweezers and very gingerly fished it out, as I didn't feel like having it drop down into the action. Had that happened, it would have been ok, as I've taken the action out a million times, as I do almost all regulation myself, depending on the tech only for the really esoteric stuff. So I still could have retrieved that fragment, but with the additional inconvenience and aggravation. Needless to say, I then bought a high quality tuning lever!
On large hands: My technical routine is to do all scales major and harmonic minor working downward by thirds, then the next time upward. Same with arpeggios. There are a couple of scales that give me fits for the reason you mention--getting fingers stuck between the black keys especially if I'm sitting a bit too close.
Speaking of sitting, I got a new Jansen artist bench today to replace my 23 year old Concerto artist bench. The Jansen is superior, and I love it. So comfortable!
I'm surprised with large hands that you do so well with Mozart. Usually it's the pianists with small hands who really excel at it. My hat is off to you! I could never play Mozart like that.