I've done this mod myself (partially) as I'm waiting for some 3D printed sliders to complete the mod. (WIP image of the mod here:
https://imgur.com/a/bQ6MymZ )
Firstly, the LCTRL housing is not standard as to allow a LED light to shine through. You'll need to desolder the LED first which shouldn't take more than a few seconds. Next the shape of the socket is not the same as the others, so you'll need to use a Dremel and/or a file to make it socket larger in order to fit in a standard housing. I used a Novatouch housing afterwards, but probably you might be able to use the existing housing with the KBDfans sliders.
For the spacebar, on the Realforce this is a 6u spacebar, which won't be compatible with most MX sets (I think most sets don't come with 6u spacebars, and even if they do, the housings are not the same). Also, most aftermarket sliders won't have any spacebar stablizers anyway, so you'll need to get a bit creative here.
Your options are to stick with stock Topre spacebars, or buy the 3D printed Shapeways sliders (Google it), but there are versions for 6u and 6.25u spacebars. Do note you will have to mod the plate if you go down this route as the bottom row is non standard.
I have the Shapeway sliders coming in today, so I can only comment how effective they are after I do the mod.
Also, do remember to cover up the other parts of the keyboard, as you do not want metal dust getting into the sliders. Also, maybe consider some thin lube on the slider rails, as the KBDfans sliders could be a bit scratchier than stock Topre ones.
Two users have done this same mod on these forums, and here are the links to them:
https://geekhack.org/index.php?topic=93802.0https://geekhack.org/index.php?topic=93076.0Good luck.