Bob, honestly I do not know the 125mm Pentax (although I read some good things about it especially for wide field medium format shooting: this is another scope few people own anyway.), but I seriously hope that the performance is better than the other Pentax I've seen... They are just horrible in the blue! I don't know why so few people notice that. Even if you can of course eliminate it, makes one think about using the word APO for them.

What about a flattener for the 130? What did you use?
What are the differences you mention in the lens cells? Are they both collimatable?