"Not@home" wrote in message

I haven't selected the models yet, but the ones I have looked at seem to
have different footprints. I want the pad to be big enough to accommodate
whatever models we buy, but not so big that it is a tripping hazard.

So what would be a good size to make this?

Make it big enough to accommodate whatever models you buy, but no so big
that it is a tripping hazard.

Why don't you look at the specifications for various machines?