Below are just my thoughts and aren't backed up by any study, just my personal opinion based on my experience with hairloss, AAS, and research.
To start with, I don't buy the "AAS don't start MPB, they just accelarate it if you're prone to MPB".
Of course I fully admit that AAS are not the best shampoo ever, it's not what I question, what I question is what "prone to MPB" mean.
If you lose your hair at 20/25yo like some unfortunate folks, or even younger (I had a friend back in High school who started shedding severly at 17yo), you're def "prone to MPB".
But in the other hand I've never seen a 70yo guy with his teen age scalp...Fact his, men shed hair when they age. So of course if you're bald before 30, you can state that you're "prone to MPB".
But what if your hair start thinning at 40, 45? Are you "prone to MPB" or just aging normally?
My boss is almost 50, and his hair is def thinner on the scalp. However he doesn't have bald spots, etc...His hair is of a normal lenght, but if he were to have them short then I guess the thinning would be quite obvious. But because he's 50 and don't show any bald spots or obvious strong thinning area no one would ever look at him and think "this guy is prone to MPB".
What I'm trying to explain is that this "prone to MPB" is a very blurry thing...At what age, and at which level of thinning, is someone considered "prone to MBP"?
Now the AAS thing. They can accelerate shedding, but also trigger it. You can also shed hair during cycle and get them back to normal a few months later. Then you can suddenly shed hair from a cycle you're already ran 12 times before without any issue and never get them back. There's no rule.
And this "no rule" also apply to the AAS you're using. My first cycle was Test-E 500mg/week / 14 weeks. Didn't lose any. My second was Test-E 300/Eq 500 / 15 weeks and I shed quite serioulsy, for the first time of my life, I was 33 and still had my 15yo thick scalp, and this cycle was supposed to be easier on the hair.
The my third was Test-E 750mg/w/14 weeks, something that should had hit them harder than the Test/Eq one. I was a bit frisky so I used Spiro and Minoxidil. Not only didn't I shed one hair, but over the few months following my PCT (I used Spiro/Minox only during the cycle) I got my original pre-Test/Eq scalp back.
According to my first Test-E cycle without any problem, I'm not "prone to MPB". I shouldn't have shed any during the Test/Eq cycle. But I did, so I am "prone to MPB". But then the third cycle shoud have made things worse, but they didn't. Then my hair recovered, so what? I'm "not probe to MPB" and therefore AAS won't hurt whatever I take? I doubt it.
All that to say that unfortunately there's no rule, neither on "how prone to MPB" you are neither on how "safe" an AAS is. Anavar (var) is supposed to be super safe but you had shedding even though most people say that until you're super prone and run it above 100mg/day it won't hurt. Some shed on Test but rip through DHT derivative without dropping an hair, for others that's the opposite, etc...
You're already on Finasteride, so I would just recommend to add some topicals like Minoxidil and Spiro and then run your cycle and question if your hair is more important than your goals if you shed. Of course someone balding at 20 would probably not do well on a Test / Tren / Winstrol (winny) cycle, but AAS and hair are a kind of russian roulette, you don't know until you've pulled the trigger.
Just my 2cts, nothing else, as I said it is not backed by any scientific data.
