I read over and over that everyone says low bf is what causes vascularity. Which it does but I think certain compounds can help more. Anytime I'm on a cycle my vascularity increases. Even your first test only cycle you should notice a pretty good increase. Tren gives me some crazy vascularity. EQ did too but I believe that had to do with my bp going up.
Now I feel like my pumps at the gym have been absolutely crazy lately and it is from Igf DES. It's hard to compare anything to tren but the vascularity is insane. Especially because I'm nowhere near as low on bf as I am on tren. (which I take in cutting phases during the summer.) So if it vascularity you are looking for I would suggest checking out the DES.