Johnny,
I have been lucky, all my Brooks saddles have broken in over the first 200 - 300 miles of riding. I have applied proofide infrequently and taken care to keep the saddles dry. The breaking in results in the saddle taking a slight dip along its length and sit marks appearing where your pelvic bones press into it. It feels comfortable to sit on rather than just hard and flat. Brooks saddles are also slippy, which I like, but it may take getting used to. You don't stick to a Brooks, and you don't get hot and sweaty like on a plastic saddle.
One saddle, a Conquest, was proofided much more frequently and that one sagged one day on a wet ride, I tried tension & lacing to get it back in shape but gave up and tossed it eventually.
My son rides a Specialised Rockhopper steel framed bike. The saddle it came with was a basic plastic Specialised one which looked 'racy' and appealed to a young man. It measures 145 mm across the widest point, but it provides support for about 120 mm. The B17 replacing it measures more like 170 mm across and most of that provides support. I can see from the sit marks on the B17 that the specialised saddle was supporting my son by taking his weight on the groin between the pelvic support bones. No wonder it was causing pain and discomfort.
Another son rides the same model of bike and is happy with the narrow plastic saddle. We are all different shapes and luckily saddles are also made in a variety of shapes. There is one out there for each of us.
I have never used a saddle with an anatomical cutout, but have read many good posts regarding the ones made in America. It seems like a good idea if you are troubled by a normal saddle in that area. I would recommend trying to get a ride on a B17 equipped bike and, if you like the saddle, buy one or the Imperial with the cutout. Brooks saddles sell well secondhand if you change your mind about it.
Julian