You'll only need a 1/4 teaspoonful pumice,
but as it is not sold in smaller bags you will have to plenty.
What is the feltpad used for, pumicing, finishing?
Old white T-shirts will do the trick.
You can make a same kind of rubber(muneca) for pumicing as you make for french polishing.
Do you have the Milburn manual for french polishing - it helps alot.
To crown the frets I only use a very cheapo quatershaped ¨diamond¨ file and finish the crowning with different grades of sandpapers and steelwool.