Yo cafe latte:
I do not think it is worth your while to get a sapphire stylus for a 78 RPM player. Those are pretty much unavailable any more and most 78 styli are diamonds, which are much longer lasting.
It is very rare to find a truly pristine (unplayed) 78. Most of the records you will find are pretty seriously worn and noisy. You can choose a number of styli, going from about 2 mils to 3.5 mils. Stanton 500 has lots of selections, and you can spend lot$ of money on styli. I just bought a generic 3 mil conical diamond 78 RPM stylus for my Shure M44, and it is OK, but not great. It does give more impact than the 2 mil stylus in my V-15 IV. I try both and use the one that gives better reproduction.
DO NOT USE an old gramophone to play 78's. First. they are not good for any electric record made after about 1925, since those were set up to be reproduced electronically. I say use the most modern cartridge you can get, since it will minimize the wear and deterioration that the record will suffer due to excessive tracking forces and low compliance of acoustic reproducers. Wear is the big problem with 78's.
Depending on how much you use it, a diamond 78 stylus will last a couple of years, but if you are using it 3 or 4 hours a day, I'd check it every month. 78's are rough on styli.
You can cheat and use the RIAA curve in conventional preamp, but you will have to turn treble up a little bit to get back sibilants. Sometimes a sharp cutoff filter at 5 kHz will get rid of way HF noise.
I have never had a preamp that had all the 78 RPM equalization characteristics. I do the best I can with a 5 band Heathkit tone control and an old PAS-3x with a homemade outboard equalizer box with RCA, LP, AES and NAB curves in it, fudging with box curves and the tone controls. KAB makes a really excellent multiple EQ box, which really co$t$, but they say it's great. It's my 78 dream to be able to equalize correctly for the records. If you have the buck$ it would be worthwhile, but you really have to play lots of 78's to justify it.
And good luck from that well worn, but still highly electric old guy,