I have a cheese press my husband built me. I use weights from an old weight machine. The recipe calls for moderate weight, O.K. how much is that?? I have been using 25 lbs but I am just taking a wild guess!
breezy, the weight would depend on the type of cheese you're making, and even then there are options. It would also depend on your molds, etc. What's the cheese, and what molds - dimensions - are you using?
Like Arnaud says the size of the mold is important. Take a look at this http://sturdypress.com/?page_id=201 (http://sturdypress.com/?page_id=201)
Also search the forum for the same type of cheese you made and I am sure that you will find some notes about what PSI to use for that type. You need to start thinking in terms of what PSI you need for the particular type you are making. You can find lots of information on that also. Once you have that PSI guideline and your hoop size(in square inches) you can determine with confidence how much "weight" to use in your cheese makes. I have attached a PSI calculating chart that was posted and prepared by another member for you to look at.