Thank you for the info.  How are those wheels doing?  Did you ever get a weight on them?

thanks!

Thank you Rubybear!  Great news about the dropper.

Are you able to flip the RCT switch on the Super Deluxe when installed? 

thanks again.

Well, I found a thread on MTBR that indicates it's possible to run the RS Super Deluxe Ultimate RTC on the FS958 but the switch may not be accessible. 
https://www.mtbr.com/threads/light-carbon-fs937-downcountry-29er-build.1101497/page-5

FWIW

I just ordered a LCFS958.  I have a question for those of you that have have built one already. Has anyone run a RockShox Super Deluxe Ultimate rear shock or any piggyback reservoir shock? If not, for those with the frame, would a shock with a piggyback fit?
Thank you in advanced!