Wow!! Thanks folks for all the great advice and opinions. I was absolutely persuaded by each and every post here concerning 1 vs. 2 blades. I even felt myself "ping ponging" back and forth concerning the overall merits of each choice. You all made compelling cases, I could have gone either way and I'm sure been very happy. Had I been able to handle both knives the choice would have been easy, as one would have called out to me, but on the Web choices are more remote.
I decided to look for both a 1- and a 2-blade Pemberton to see what was available. The production run was finished months ago and they are scarcer in the wild now. I knew I wanted either the Autumn Gold or Black Olive jigged bone--those were at the top of my list. The Autumn was only made with 2-blades and in the nicer and more expensive UN-X-LD version. The Black Olive was only made with 1 blade and in the more utilitarian Tidioute version. So, choosing via covers would lock me into the number of blades, detailing, and the price point.
I had almost decided to go with Black Olive to experience a small, single-bladed knife (I have 3 Case Peanuts already), but I could only find one available for sale and it was serialized and therefore commanded a price premium. I also found the 2-blade UN-X-LD Autumn Gold version for sale, and because it was unserialized it only cost $12 more than the serialized Black Olive. Only $12 extra dollars for Autumn Gold, the threaded, dimpled bolsters, the long pull, the chance to trade "down" if I decided I want a 1-blade Tidioute version instead. Everything but extreme thinness stacked up in favor of 2 blades. Plus, I could always have the pen blade removed if it really bothered me.
But now I can put evaluating aside and I know I'll love it! I normally sharpen a pen blade down to 12-13 degrees and make a scalpel out of it. If this pen blade is as thick as people say, I might leave it obtuse and use it as my poking/prodding/scraping/clean-the-battery blade. That might open new vistas to my extreme affinity for slicing with acute blades.
Thanks especially to those who gave measurements/photos in this and the other related threads. They really helped. When i saw that the 2-blade version was actually slightly thinner than the Peanut, and only barely thicker than the single-spring #33 Conductor, that made the choice easier. When I read the weight was very close to a Peanut, that clinched the deal. i guess because the Pemberton is wide (though not thick), it just looks big and heavy in pics.
Can't wait to try it out. Thank you all!! I was able to find it at a BF-supporting dealer. And thanks to the two that chimed in here. They are the first I have always gone to when looking and buying.