Stock set up. Recommendations for replacement clutch and any tips for installation etc very much appreciated. Made it to 105K miles on OEM clutch...

I am towing 10K pound gooseneck trailer.

 

You looking for a upgraded clutch or are just wanting a stock HP clutch

 

I want the best clutch for towing--my truck is bone stcok except for cat back exhaust.

 

I would look at the south bend ofek with upgraded hyrdos and flywheel and its rated to 450HP

 

Thanks for that info--question: Why would this be better the G56-OK clutch?

 

First off your lucky you made it that long on a dual mass flywheel.
The south bend eliminates the dual mass which gets rid of the chance of the flywheel coming apart which is very comon.
I'd say southbend also. But I've had issues with their low grade single discs not lasting long. Personaly if I was to put one in I'd do the 3250 Double disc and be done with it.
It will handle all the weight you can throw at it and it will handle over 500 rwhp without an issue if you ever get to that. It can also take being sliped once in awhile.