the largest Ive seen are 5X5 and the 1X10
But you will often see them cut down to 1X5 too, but dont know if they were issued that way or cut later.
Baseball are W590, but these sheets also include other sports and W589 cards.
The boxers from the same series are sometimes called W580 but W580 in the ACC is said to be related to the baseball W572's so I dont think its correct unless you say W580-1, etc.
If you do an eBay search of "1923 W580" you will see boxers and movie stars etc listed but I believe most are related to W572 because they have the wider left and right borders and caption is slight different font.
here is a W589 strip of 10
http://sports.ha.com/common/view_ite...2&Lot_No=42164
here are the W580 (W572 like)
http://shop.ebay.com/i.html?_nkw=192....c0.m270.l1313