Testosterone is sufficient for a first cycle. It is already produced in the body. It is all purpose because it accomplishes enhanced recovery, improved endurance, increased muscle mass, improved strength, increased appetite, and lean mass preservation through its anti-catabolic effects. It can be used for gaining mass, gaining strength, gaining energy, gaining stamina, preventing muscle loss, working out longer, working out harder, working out more frequently, and the list goes on. It is basic, intended for human use, and well tolerated among men. The side effects are known and documented. A low dose will be the best way to go. It will provide significant benefits with mitigated risks. The bloating, oily/acne skin, formation of breast tissue, cardiac hypertrophy, blood thickening, are less of a risk at low doses. Moreover, natural production usually returns to normal levels easily within a few months; depending on doses, post cycle therapy may be minimal or not needed.
On the other hand, testosterone doesn't support acquisition of quality lean gains. When natural production decreases and the outside source ceases, then fairly rapid detransformation will ensue. If one continues a vigorous regimen, the detransformation will be less drastic. However, detransformation will usually accompany psychological discouragement, sloppy look, reduced motivation to work out because it will merely slow down and somewhat limit the process and feeling of going backwards.
A one off cycle does not make sense because the benefits of a cycle are never sustainable far beyond the post cycle period. It will not capture natural muscle gains to any greater degree than what one would naturally be able to shoulder; the faster natural levels return to normal, the slower the losses. The natural level will determine the long term balance of what is possible. Ultimately, the best case scenario is exogenous test increases blood testosterone levels beyond normal, then through careful diet, smart programming, and vigorous training one achieves gains in lean mass to an abnormal degree concomitant with supraphysiological doses; finally, the exogenous administration ceases, diet gets strict and training is continued at maximum intensity to delay the descent from on cycle numbers; soon, the person's natural levels have recovered and their persistence during down time has left them slightly ahead (temporarily) what they would have progressed naturally had they never taken testosterone in the first place.
250 mg test cyp/enth a week improves performance and composition. It will put one above normal levels. Splitting the dose and administering twice weekly should help to maintain more consistent levels in the blood. The benefit of twice weekly injection would be as one shot is wearing off, another shot is taking effect, and the peaks and troughs are less extreme. It's a modest effect, considering 10-11 day half life for cyp/enth - the way I see it.
Blood work, blood pressure checks, avoiding side effect exacerbating substances and contraindications, adding training weights in small increments, preventing overuse, eating calories to support growth and no more, avoiding salty foods, doing regular cardio, resting adequately, and being prepared to cut a cycle short or come off cycle: mentally and consciously; and knowing what can be done to alleviate lingering side effects of being on cycle, namely suppressed natural production, gynecomastia, acne, hair loss.