After playing around with several different heights, angles, fore-aft positions, screw tension, and lacing tension with my Flyer Imperial, I found a setup that I think is the best I could get from it, but it is still not good enough for me, as I still feel a little discomfort in the perineum after 1 hour that gradually increases over more time. So I'm going to give up on Brooks, and start trying synthetic saddles again, although I've already tested several others.

The problem for me is always the upturned middle part to the nose of the saddle that applies pressure to my perineum. The cutout may reduce the contact by a couple millimeters, but I still get contact when going over bumpy roads or changes in elevation that cause me to slide around. So I need the entire forward part of the saddle to be leveled or pointed downward. But I will share some of the adjustments that I made to make the saddle a little more comfortable.
[MENTION=442862]RECfromPA[/MENTION] I'm not able to measure the distance now, but you could also try making your own cutout on your old Flyer. It's easy to cut with a boxcutter. You will need to drill holes in the sides and lace it. I did this to my old Flyer, but it was "old" and already stretched to the max, so it eventually sagged into disuse.

Tilt: I made it -2 degrees downward with the bubble level stick laid all the way across from front to rear, while unloaded. I measured the angle precisely by putting my phone on the stick with the clinometer app. When I press down on the saddle to compress the springs to simulate load, the rear will drop below the nose until the app measures a +1 degree tilt upward. If I tried tilting the saddle any further downward, I would slip forward. If I tiled the saddle any further upward, I would start to feel increased pressure on the perineum.

Screw tension: I tired several different tensions. I could feel a big difference in sagging with my butt, with only a couple revolutions of the screw/nut. I increased the tension and it greatly reduced nose contact with my perineum. However this increased stiffness at the sitbones and they got a little more sore, but with bicycle shorts I could not feel the effects of the increased stiffness.

Height: If the saddle was too high, then I would feel more pressure on the perineum.

Lacing tension: I found that lacing the front holes didn't help. But if I also completely laced all of the rear holes, the sagging would reduce greatly. This would increase stiffness at the sitbones, but bike shorts countered this. For the lacing of the front holes, I wrapped the string underneath the rails to help reduce the height of the nose by a minuscule amount.