Seriak,
They will be ready in about 3 to 4 weeks.
They are about dime to nickle size now and are best to go at quarter size.
As far as substrate, use what ever suites your fancy.I have alot of plants in my angel tank and I have mixed substrate from 2 to 5mm in diameter.
I usually have quite a few extra live plants in my angel tank but they dont seem to be growing as well latley. When you get the angels I will probably have some extra to give you as well instead of throwing out.
You can reach me @
h-235-6467
jon_kate@telusplanet.net