It seems to me that this question needs to be broken down in terms of what is meant by “safe.”
Just being a little facetious, if the definition of safe is being sure not to grow two heads, then all androgens are safe.
Whereas if risk of producing an acne pimple is deemed unsafe, then all kinds of things will be unsafe.
So what risks are you worried about?
Liver toxicity: no problem if not using orals, not much problem if using orals for relatively modest periods of time such as 8 weeks and being off of orals just as much during the year as being on them, or at most not more than twice as often on as off.
Hair loss: if you have the genetics for it all androgens except low dose Deca give some risk here.
Acne, particularly back and shoulders: a quite likely risk, oddly enough even moreso post-cycle.
Prostate enlargement: Probably not an issue if not letting estrogen get high at the same time.
Estrogen-related problems: Not a problem if using no aromatizables or a quantity minimal enough to maintain normal estrogen.
How post-cycle can be affected is a little more complicated but not much so, mostly affected by half-life and some effect from progestagenic effect if any, maybe some difference on estrogen level as well.
As for steroid books and articles claiming slightly different esters of the same parent steroid to be substantively different in character or safety, that calls into question the judgment of the author I think.