Like the look of your sewing room UttaRetch, now with regards to your cutting out mat, why not get something non slip to put underneath to stop it from moving. Whilst my cutting out table is not super wide, I do put a cutting out board on top to save the surface really, but I tend to lay strips of a non slip rubbery mesh between the board and table and then find I more of often or not I work with the board up 'close and personal', so much easier for me when laying things out, measuring - but then I am not particularly tall so that may make a difference.
So changing subject ever so slightly, how long before you can take up residence in this room?