Great looking set, Congrats!....keep us posted to your progress with cycles and options....
for the most part, have not heard of machines walking off of platforms, whether home made or built in, not saying that it could not happen, for a safety measure, a small strip could be placed in front to prevent a machine from walking forward and falling off...surprised there isn't a wired type of device to secure this to the wall......well, in this case, thankful nothing bad has happened yet, but you can be sure, once this happens to someone, anti-tip over devices will be added like with stoves....
I have pedestals on my Frigidaire pair in the main bathroom, in my case they double as laundry hampers, whites under the washer and colors under the dryer...once full, its time to run a load....yes, they can be pricey, got mine at a Sears outlet, 100.00 for the pair.....
and for this set, once I raised them, I can't easily get to my valves....so for this setup, I am considering something like this....not to mention flood safe since this is on the main level, and a drain pan was not installed.......
something like this may help in your situation...
there are other versions, some with a timer that allows the water to be 'on' for a short time, but I like this one because its automatic, and also will detect leaks on the floor and shut off the water and the machine....