Post-Christmas shopping

I have pillaged John Lewis, put Sainsbury's to fire and the credit card, and run amok through Lakeland. And ended up with a bread-maker (which has made me a loaf of nice bread), a large blender (though my brother points out that soup recipes requiring long preparation and special equipment, and at the end of which you inevitably have soup, are probably not his thing), and a splendid chrome-wire flat-pack mathom stand. It's quite a clever design; there are sixteen lengths of solid chromed pipe, threaded at both ends and equipped with deep grooves at regular intervals which are neither an inch nor 25mm, which you screw together into four side-pieces. You slide the seven baskets onto these side-pieces. To hold them on, there are twenty-eight slightly tapered plastic bits, which come in two parts that clip together, and which have ridges on the inside which click into the grooves; the cylindrical sections at the edge of the baskets are wider than the top of the taper and narrower than the bottom, so slide on and are held solidly by gravity. On the top shelf, mathoms made of textiles. Then gym kit. Then my disconcertingly large collection of external hard disc drives (unused). Then a couple of desk-tidies filled with Miscellaneous Stuff (batteries, a complicated wire-stripping tool, a set of theatre gel samples, a Barlow lens) and surrounded by Miscellaneous Stuff comprising mostly adaptors for using English plugs in foreign parts and foreign plugs in England. A shelf of cameras, a shelf of extra lenses of moderately inconvenient size for cameras, and a shelf for flat paper mathoms at the bottom. Soon I can get rid of the large and ugly table that I used to keep my computer on, and then used as the base for a substantial collection of intimately-mingled mathoms and trash; the mathoms are in the mathom stand, and the trash in the recycling box. I always feel a little guilty disposing of paper Economists, but the Economist archives are on line. A question for the domestic: if I have cushion covers which measure 40cm square and 45cm square unstuffed, how large should I buy the cushions to put in them?