Pressure is size dependent (force*area) ,so the pressure is dependent on the diameter of mould your using.
Applying 50 pounds on a 4 inch and and an 6 inch mould will produce very different results.
Its a good idea to contact the book author and ask what size mould he used for his recipes and adjust (multiply or devide) to your size.
With chedder for example you really want to load everything you've got without cracking the press for the final pressing, and even then you wont reach the "required" pressure with a 3-4X force multiplier dutch press, for that amount of pressure you'l need a pnuematic press or a dutch press with a pully system which can give much higher X factor.
Yours will still turn out great,just slightly moister and you will need to dry it in the cave for 3-4 weeks before you wax.