Brooks recommends a slight up-tilt. Brooks saddles are like no other, and you may set the thing as close to your old settings as you can, and still have a completely different feel when you get on it for the first time.

Some 17's come from the factory with a dead flat spine, while others come with a slight concave, or even a convex spine. It doesn't matter. Even though you have your's set level right now, it will flex concave immediately as you begin riding. After 200 to 700 miles, it will stay that way for a very long time. If you ride it level, the flex will dump you forward onto your perineum, with the seat portion high. This might work for you, but I doubt it.

Set up the saddle so just the seat portion is level with the ground. The peak will end up where it will. It's purpose is to keep you back where you belong - on your ischials, not your perineum. But, the setup needs to be done in conjunction with the handlebars, which, with a 17, should be level with, or above the peak. It's not a racing saddle. If you feel pressure on the perineum, scoot the saddle forward a little, maybe 2 or 3 mm at a time, keeping an eye on Knee Over Pedal (not a huge factor as long as you stay in the ball park).

Take a good look at the saddles you see that are raised in front. I think you'll notice that the seat portion is about level on most of them. With proper bar height, and good for and aft placement, you won't even feel the peak at all. Counter-intuitive, but true.