Our club also uses C-clamps to secure the modules together and thumb screws into t-nuts to attach the legs.
I am using hex bolts and t-nuts in my new layout, as shown below. I use them to secure modules together and to attach the legs to the modules. A socket on the drill make short work of attaching and tightening. Plus, it draws the t-nut tight. I recessed anything along the front so as not to interfere with the facia.