Good news! There is a secretly easy way
.... dipping, not pouring.
Bake your cake sheet and if you want to torte and fill, simple syrup them or whatever you want to do. If you want a traditional marzipan top, do that now to the whole sheet. At my shop, we add a thin layer of SMBC to the top and make sure it's super smooth. This will eliminate any imperfections in the cake surface.
Now freeze this bad boy solid and then cut into the desired size. For us, petit fours are 1x1x1" and petit fives are 2x2x2". Refreeze.
Make the "Quick Pour Fondant Icing" off of allrecipes.com and heat over a double boiler until it thins and is fairly warm. I have never used a thermometer, but I'd say its about 120 degrees F.
Your dipping set up will be a sheet tray, something high in the center (I like a full 5# fondant bucket), a glazing rack (like shown in the video), then something heavy to keep it from spinning or slipping (like another fondant bucket).
Pull out as many petit fours and you can dip before they soften (I can do like 30) and QUICKLY flip them over, insert a bamboo skewer (shortened if necessary), dip into fondant, turn it right side up, insert skewer into a hole in the rack, lower petit four to rack, remove skewer. Repeat. This is a bit of set up, but once you are going it is FAST. The excess fondant drips off (you can't re-use it but there isn't nearly as much run-off as in the video) and the warm fondant sets up very quickly against the frozen cake. By the time the tray is full, you can handle the first ones and put them into their cups (a paring knife or small offset spat will assist you.)