Hi Seppet, basically really simple -as I did it!
Measure rice in Volume in a measuring jug, so if you are thinking of 300cc implants, measure that much rice pour into a pair of tights, mould into implant shape, tie a know and hey presto! pop in your bra to get an idea of size!
I walked around with rice bags in my bra all day the other wkend my BF thought I was nuts! xxx