First, I am in your size range, 6'4" and today 265#, but was 279# 4 weeks ago. (Changed eating habit to get through the wall, and also some more riding time with weather improving.)

I have several bikes, the three I ride the most frequent are fitted (in order of frequency) a B68 on a Hybrid set in more upright position, B17 Imperial, Schwinn Continental, and a a B17 (new) sharing duty between to road bikes, a project 73 Super Sport and a 76 Superior.

All three bikes and saddles are comfortable, including the B17. The B68 is used on rides with the wife, 10 - 12 mile rides, usually every night and twice on weekends. The B17 Imperial has seen the longer distances, 60 - 75 miles a few times last year, and the longest this spring 29 miles.

I find, extending my legs and rising from the saddle helps me to relieve my back side of any numbness and also to correct my posture while riding.

My rule for a comfortable saddle, regardless of the distance I ride, is when I am off the bike, the ghost saddle is not felt, ever.

Before my Brooks, I could feel my bike saddle(s) for hours, and once a day plus an evening. I do not think I will need to try any more saddles, and consider myself fortunate to have found the Brooks B17 series fit me properly.

My son who is 6'7" learned that his sit bones are a bit wider than standard saddles, found a model of Specialized gel style better fitted and has no more issues with pain there or in the lower back when he rides.

If your saddle fits and provides comfort, then all will be good, it is natural to search for something better, or it may just be a slight adjustment. Try sliding it forward or back a little, even try tilting the nose up if level, or level if presently up.

At this time you should be observing the indentations on the B17 where your sitbones are resting, if the saddle is to forward then you are riding on the rivets, an error I have seen on more than one occasion. The same can occur if to far back, you are sitting on the nose area and supporting more of your upper body with your arms, not as comfortable as you can be.

PS: Riding shorts is a good idea, I just have not gone that route yet. I do select shorts with flat center seam, and no seam on undergarment. Same for legged pants, usually a nylon wind pant over the same shorts. Just haven't bought Lycra type garments, maybe some day.