You can't tell much from just a few minutes in one position or another. You really have to ride for a couple of hours between adjustments. And EXPECT to be sore the first few days. When I first tilted my nose up, my girly bits felt sort of squashed. After a few hours they were fine and have stayed fine. Odd but true. Having the nose tipped down was much more unpleasant, feeling I was sliding off forward onto my hands.

Set the saddle in the middle of the brackets, forward/back wise. Tilt the saddle somewhere between nose-up/squashed girly bits, and nose-down/sliding forward feeling. Then ride for a day or two and make more tiny adjustments. There IS no magic position to make a hard new Brooks will feel wonderful for the first week. Unless you are just weird and lucky.

In fact, the first few rides will leave your sit bones sore. They will adapt and feel better after a few more rides. Just have faith that every 2 or 3 rides will feel a little more comfortable, and by a month (with weekly HideProofing) it will start to feel like riding on nothing much at all, like sitting in a nice carved Winsor chair, you don't think about it when it doesn't hurt!
Plastic, gel, and foam saddles stay the same as when you buy them. But leather slowly changes shape and forms to you like a good pair of fine leather shoes, or a favorite belt. So you can't tell what it will feel like as it shapes to you. This just won't happen in a couple of hours on a trainer.