I just breezed through this thread and notice the quest for a flat seat that won't constantly slide you forward. But don't want to make it taller.Just did a review on these. https://www.st-owners.com/forums/showthread.php?133590-Review-of-MCL-seat-riser-brackets I had to take them off because of my 29" inseam was a little to short for them wth the russel seat on, otherwise very comfortable.
For those that are asking I sold these risers to another forum member that is going to try them out.
I was able to accomplish that via a different method. If interested, you can find it and some photos here:
I customized my seat for touring