Electroplating

Surface Area and time---the molar quantity of the plating material is governed by the current (amperes), the charge on the plating material and the plating efficiency. As these are controlled during the plating process the variable are the surface area of the piece being plated and the time it is being plated.

Rap

You need also to determine a distance from the part to be plated and the electrodes.

This determines the regularity of the plating.

Mea Culpa, Timur. Yes the diffusion length of the ion from the electrode through the plating solution would have an effect on the disposition.

Rap

After we separate asbestos from rock samples when we do assay analyses we infrequently plate metal Gooch filters onto which the asbestos fibers had been deposited, with a fine layer of Cu metal in order to "plate" over asbestos fibers so we can count them using EE microscopy. In ours we use the item to be plated as one of the anodes and a copper sacrificial anode as the other. Its all in a (pH adjusted) solution of copperas and 0.1M copper sulfate. We just make up stock slutions and store em in a carbouy.
I think most plating uses the item to be plated as an anode as well. I don't have a lot of experience but we use a current of about0.01 mA and our results are very good.

McRone technique used to plate gold onto the microscopy samples.

If youre interested in Brass plating and are going to deposit on iron or a ferrous metal and you ont wanna go through all the intermediate steps, Ive found that a "blacksmith" approach works really well. HEat the iron item till cherry red and then hold and BRUSH it with a brass brush. Thi deposits a very classy amount of brass onto the iron without hving to put nickel or copper down first.
Then you can plate directly using the anode method .