1.) A thing/tool I use, an excel sheet I made that that tracks my calories, macros, fiber, micros, electrolytes, fluids, body metrics like body weight, body fat, body measurements, and progress pictures on a daily or weekly basis respectively. That same tool also tracks my sets, reps, weights, time in the gym, training frequency, cardio, and heart rate. I use that data and what I have learned about training and nutrition to adjust my diet and training on a weekly, or bi weekly basis. Lastly, I ensure that I follow said plan with 90% accuracy, 100% of the time, and that I go to bed and wake up at the same time every night (weekends included). This tool is what I use that allows me to continue to enhance muscle growth and improve physical fitness on a weekly basis, consistently and reliability, with the least unwanted side effects possible since 2012.
I leverage testosterone (up to the dose I can handle without side effects), primo (to add any additional required AAS load beyond what testosterone dose is implemented), and Nolvadex on an as-needed basis to prevent gyno if it comes up while I titrate said doses back down within the range I can handle (without this negative estrogenic side effect, and without the need for an AI at all).
2.) Number 1 has good effects indicated by continual progress with consistently acceptable ranges (relative to the stresses on the respective systems) on my bloodwork, blood glucose, and blood pressure. The negative side effects however are that I do not typically get to stay up past midnight, that I am not allowed not gorge myself any time I go to a restaurant, and that it takes a good amount of time investment to plan, adjust, and execute the diet and training plan.
Everybody's bodies and goals are different, but I have found that the pros and the results of the above are consistent in allowing me to enhance muscle growth and improve physical fitness without negative, unwanted side effects.