What door thickness is this handle set compatible with?

Thanks for reaching out to us. The 40-049 is specifically designed for 1" thick doors. That said, I've known it to work on doors up to 1-1/2" thick in the past. Just note that that's not always possible, since it would depend more on the door itself, but I've seen it happen. 1-3/8" is well within the realm of possibility, even if it's not a guarantee.

As for a dummy version of this handle, I'm afraid we don't sell anything like that. I've honestly never seen a dummy storm door. Are you using this for a storm door, or something else?