are you getting ready for selection? if so, I don't think you will be able to retain much of the gains from the cycle through PCT into the course... if you don't mind, please clarify if this is your plan.
moderate dose (300 mg/wk) adds a bit of muscle, but will definitely increase your strength to weight ratio. also, it will increase red blood cells, which will increase your endurance capacity. higher doses will result in more muscle, but for you that might be unnecessary weight to carry around.
attached below is a study that used varying doses of testosterone that can give you an idea what to expect:
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