@gunrunnerjohn The ones I have and I think Craftech has are the low profile versions (purchased in store at Menards in the electrical section):
They average about 0.32" thick (a hair over 5/16) and fit nicely under FasTrack roadbed if you avoid putting them under the rail tabs.
@Craftech If you need the levers to stay closed temporarily, a thin half wrap of tape should hold the levers down while you attach the roadbed to the base.
