I'd also go for the vari mag.
I've done things like turned the mag adjuster until a 15mm has given half a mil dot at 25 yards ( and usually a full mil dot at 13 yards ).
So I don't tend to place a set mag on the scope ... I just turn the mag to suit a certain set up. So if you asked me what mag I shot HFT at I wouldn't know. Or at least it wouldn't be at a certain number on the dial ... somewhere between 9 and 8. As already said the mag numbers don't mean they are accurate anyway.