Hi Ockius,
Welcome to the best era in historical wargaming (IMHO!:)) And one of the best, if not the best, rules set out there! I have been playing GdB for about 15yrs. It is an excellent set of rules.
As for your question. It is a little difficult to answer, as for GdB, there is no 'set' basing. The rules have a system of regimental sizes based on a ~1:20 ratio of minis to men. So for a cavalry regiment this normally gives 9, 12, 16, 18 figure per unit depending on the date and the unit. I know there are some Austiran cav regiments in the books, that in theory would have 32mins per unit. But this is their paper strength, and they would operate in wings anyway. But I digress.
The rules practice a mixture of book keeping and casualty removal. So in theory you can base your minis individually, and do away with the book keeping, but this not advised as it would be very tough for maneuvering. I have all my 15mm Cav based on 40mm frontage bases, with 3 figures per base. It is probably the best middle ground between book keeping and casualty removal. I hope that helps, sadly I don't have any photos to hand.
Do you have a particular battle or army or theater of combat that you are starting with? There are some blogs out there which have write ups of people playing GdB, those might have better pictures.
Best,
Ed