Good question.
Test 600x is a legal steroid alternative, and not a steroid itself. More of a supplement.
Clen is a real rough corticosteroid used for asthmatics that ALSO helps shed body fat by increasing metabolism. You can only run clen in two week cycles. I choose not to run clen due to the side effects i get, such as the shakes (my signature looks like i have parkinsons when on), and the over all uneasy feeling i get. Personally, unless getting ready for a competition, I wouldn't advise taking it, as the effects are fairly temporary. However, some people manage the sides better than I do, and they don't have much of a problem with it.
I think the first thing I'd have you do is head on over to the nutrition section and post up your diet. Please include your macros per meal and total macros per day. Also include your tdee so we can benchmark off it. The safest thing you can do is to let nutrition and your workout routines get you to where you want to go. Bulking and then cutting is probably the quickest way to add some good size.
There are some peptides out there that are fairly safe you can run that will trigger a good HGH response from your pituatary and help you grow new muscle tissue. These peptides will not shut down your natural testosterone production, and have very few sides. They will also help lean you out.
Real steroids will bring a whole host of health risks, such as increased lipids and cholestoral counts, high blood pressure, increased RBC, hematocrit, possible enlargement of the prostate, to name a few.
There are countermeasures to all these risks. However, none are foolproof or 100% effective. Most on steroids do have one or more of the above mentioned sides, not counting the sexual sides as well.
If you want to talk about any of this, let me know and we can talk.
Let me know which direction you want to go
---Roman