I would second the HCG (or similar, clomid?) for anyone that wants to prevent atrophy by keeping your LH levels up. From a medical perspective I would be curious if you could play with HCG or similar by itself to cause your natural T levels to rise without having to take T.

As an anecdotal single data point of how far you can go after keeping my LH levels as low as I could after around eight months straight my testes decreased around 75% in volume.