Recommending nadrolone to someone concerned with long term suppression is a terrible idea.
I doubt the shorter cycle will make much a difference, at his age.
On a scale of 1-10 Id say that IF the long cycle was an 8 the short cycle would be about a 6, when it comes to having a permanent effect on the HPTA. Just some scale I made up to explain the point, it doesnt really represent anything concrete.
OP I think you had the same risk at age 40 (when you did your first cycle) as you do now.
If I were you Id look into TRT. Or at the most only use testosterone. And yes, if you had to choose either or, the short cycle is better than the long one. TRT + periodic blasts is a common choice for men your age who have the means to do it properly/safely.