Unfortunately, I haven't found a good way to conduct a long-term self-experiment in which I observe the effect a supraphysiological weekly dosage of testosterone has on me. However, I think I found a decent alternative.

Firstly, some stats:

21y/o male, sub-saharan descent. 173cm at 61kg of bodyweight. I have used steroids before, in a bodybuilding context but that was quite some time ago. I don't bodybuild as of now.

Experimental preparations are as follows: I have sort-of double blinded myself. I have prefilled one syringes with testosterone enanthate at a concentration of 200mg/ml. 300 mg/ml. Another syringe I prefilled with ordinary bacteriostatic water. I have - 20 minutes ago - injected my left buttcheek with the content (1ml) of one of the two syringes, I don't know which one though. I will wait at least 3 weeks (time it takes for this version of testosterone until it has cleared my body) before stabbing myself with the other syringe. In both cases, I will record any subjective effects here.

I will measure my cognitive abilities every three days using:

1. Zetamac (mental math website for processing speed)
2. Dual n-back (for working memory)
3. No. of uni slides I can work through in an arbitrary hour (for measuring productivity, I study urban planning).

How does that sound? Can you suggest any improvements (preferrably improvements which I can implement without letting others know of my plans)? 

Edit: Corrected the concentration (300mg/ml) and added the amount of testosterone I injected (1ml).