The biggest issue with buttons is to make sure they’re clean. No
investment. Anywhere. No flux either.
I’ll normally chop the sprues off with a bolt cutter, to make it
easier to fit them in the crucible later, and do make it easier to
clean them. They also usually take a spin through the sand blaster,
or at very least an ultrasonic, to blast off as much surface crud as
Chopping them up also makes it easier to make your weights. A single
100gm button is harder to deal with than a 50gm button, and a bunch
of nice, bite-sized sprues that can be thrown in anywhere.
I don’t normally pre-melt the buttons. I just put it all in the
crucible together, and bring it all up to temp. Concentrate on the
button, as it’s biggest, but it shouldn’t be that big of a deal.
As far as graining goes, don’t bother. If you want to, I’ve had good
luck dropping from waist height into a 5 gallon bucket of swirling
water. Ended up with what looked like silver popcorn, rather than
beads, but it broke the quantities up into nice manageable units. I
wouldn’t get a hot crucible anywhere near the surface of a water
bath. Seems karmically unwise.