First, unless you are running propionate, 4 weeks of test is worthless.
Second, the active half-life of enanthate is such that any anabolic effect is pretty much gone after a week. The next couple of weeks are just clearing your system.
Third, if you want to add to a cycle then try masteron (poor man's primo). Primo is just not worth it, unless you have $$$ and TRUST your supplier.
Fourth, although I haven't run primo, everything that I have read is to run it for 12 weeks plus.
Your just outthinking yourself. Do the basic 500mg/week test cycle with proper support and see how that works. If you can't afford that, spend your time making more money.