I have included footplates of various sizes in a lot of my recent models. The Railbike model is a fair example of this. Each time I have hand altered the footplate when I wanted a new size. I finally decided that what I really wanted was a parametric model so I could just dial up the sizes I was after.
Doing it parametrically gave me the opportunity to use different sized and shaped holes. This can do anything from triangular holes to circles by just changing the parameter controlling the number of sides of the holes.
I haven't included any safeguards against odd selections of parameters. So you may find your hole diameter is too big for the number of hole row you have chosen. In this case your floor grid will disappear....which you may want anyway.
Hopefully this will be useful for you. I have also created a square grid version and a diamond hole version.
You can find them with these links;
the square grid version here:
Parametric Footplate - Square Grid Pattern
and the diamond pattern version here:
Parametric Footplate - Diamond Pattern