I don't, but if you search the blue foam thread in the Cart mod forum, you'll see many examples of the 'plug' - basically it's only 1/8- 1/4 deep so the rest of the cart well is all juice. The plug just keeps it from leaking out and is the 'interface' with the bridge. There were other mods on that thread by placing a spring under the plug to keep it from falling down the well - a horizontal spring and an vertical spring. The people were using drinking straws as a 'scaffold', etc. but with the blue foam (I use marineland but their are others that would do the job) when cut oversize on both dimensions - when you squeeze it in, it itself 'acts' as a spring against the cart walls and the bridge determines it's depth once it makes contact. I've never had one fall down below that level.
Again, as mentioned in another post perhaps - the texture of the top of the foam is like it is 'singed' so there is no 'threads' there to get grabbed by any barbs in the metal mesh. I've never had that happen yet. But you have to make sure the 'top' of the foam is up. The underside can be 'fuzzy'. I pick off the whiter part of the marineland foam on the bottom.
The straw mod is the old straw mod:
http://www.e-cigarette-forum.com/forum/tips-tricks/11421-cart-mod-better-refilling.html
... and again, I use the J&J safety swab Qtip shaft - the coffee stirrers didn't work as well for me and anything larger can leak. I'm also vaping a thinned out VG so, ymmv on leaks - you might have to go a bit deeper but I really haven't heard anyone having that problem with the foam as long as it is cut oversized. I also take a diagonal cut on the top of th shaft as well to keep it off the bridge and always put it on the rounded edge of the cart well - furthest away from center. I tried
just the plug and didn't get the wicking and filling I do with the straw mod. AND unlike some, I don't remove the plug to fill - and I think the straw mod is operative there as well.