I finally got my Mashall DSL 100 head serviced and repaired today, but before I turn it on, I need to make sure I've got it set up correctly. It's currently on the 8 ohm switch on the back of the head, which will plug into the left input jack on the back of my 1960a cab, but I'm not sure which jack to plug it into on the back of my head as there are 3. I'll post a picture below to help illustrate, and if someone could tell me the correct way of setting it up, it would be really helpful! Thanks