Well the scientific quality is what's referred to as a sh!t ton. 4-DHEA converts to testosterone via two steps. A portion of it first converts to androstenediol. A percentage of this then converts to testosterone. You're probably looking at only 1 or 2 percent at most making the final conversion. There's 50mg per cap. So I'd guess 50 to 100 caps per week -- probably closer to 100.
However the truth is no one knows.
Also, please do not even consider this type of dosing. A percentage converts directly to estradiol. Of course a percentage of the test that does make the conversion also converts to estradiol. So very high doses of 4-DHEA are not advisable.