While they are outliers due to their genetics, if you see what some of these pro guys look like a few months after a show when they are on HRT / health phases, they retain most of their size and just soften up a bit. If we are talking about after a bulking phase, the devil is in the details here. It's going to come down to diet and how fat you got. This is why it's really important not to get fat, ever. Like you will gain some bodyfat on a massing phase of course, but you don't want to lose at least the outline of your abs. Why? Because the next phase will be that much harder and more likely to result in loss of lean tissue you just added.
At the competitor level, a long (5-6 month) off season usually transitions into a health phase and then a contest prep. Some contest preps will start with 6 to 8 weeks of massing and then switch compounds and cut calories to initiate the cutting (to take advantage of the increased metabolism from the massing phase). If you are just looking to add size over time, you likely do not want to go directly from a 16 - 20 week high dosage bulking blast into a cutting phase with harsher androgens. The most important thing here isn't the gear, it's the nutrition. You want to stay as lean as you can while adding tissue. Dorian Yates said this a long time ago, and Mike Mentzer said it even before he did. I don't care how much gear your are taking, if you go more than 500 cal surplus per day (accounted for based on activity level / TDEE), you are likely to get fat. It won't happen overnight and you can dial things in day by day, but if you're running compounds like nandrolone, anadrol, dbol, hihg test, etc. with surprlus calories / carbs you are going to hold some water interstitially (as well as intramuscularly, which is a good thing), but your margin for error in gaining fat is low. Remember, any fat loss that exceeds 1 to 2 lbs per week, even with gear on board, is risking losing muscle. So you don't want to gain too much too fast, for a multitude of reasons.
TLDR - I'd suggest a 250 mg cruise and if anything, increase your GH dosage post blast. It will help keep muscles full and it's very anticatabolic. Keep your training intensity high but peel back volume a little to account for the lower gear. And bring food sown just a bit, as your nutrient partitioning will be a bit off compared to where it was on blast.