Hi Tim,
Don't know if this will be any help to you, I'm no expert, but here goes.
I use this tuning on my Carter U12 - 7+5
http://www.steelguitar.com/sampleS12Tuning.htmlThe E9 pedals P1- P3 are standard Emmons, in B6 the 4th pedal is omitted, pedals 5 - 8 remain as is but now become pedals 4 -7. As you can see the "E" levers are on the right with E - Eb on RKR. The reason for this is that it free's up the left foot when working in B6 mode, i.e. if you're using the left knee to get the Eb it compromises what you can do with your left foot. I notice that the Simmons has a lock for the B6 mode so this might not be as important to you. However if you want to mix it up and swap between modes quickly it may be easier use a knee lever rather than the lock.
There are 2 ways to get the D that is lost by omitting D on string 9 on the standard E9, by using LKL or P6. So far I've mostly used LKL for this as it is often in a combination with P1 - P3 and using P6 would mean moving my right foot from the volume pedal, although it is quite a long pull from B to D on string 9.
It is my intention to play around a bit with the copedant once I have a bit more experience of playing Uni and what I want out of it, however I'm just using the the chart as is at the moment and it's working well for me.
Sorry I can't be of more help regarding the Simmons standard U12 copedant, there are more experienced players on here who could go into finer detail on these changes and the reason for them.
I reckon though you will find what works best for you once you get the guitar and try it out, months, (years), of fun (and frustration!) to be had
