When MLS Cup tickets finally go on sale to the general public today at 10 a.m., pickings will be pretty thin. Based on the latest ticketing maps on SeatGeek.com — the Sounders’ ticket manager — every seat available during the presale was sold, even after prices increased to more than $100 for seats in the far reaches of the upper deck. It appears a handful of sections and possibly some assorted seats elsewhere were held back for the public sale.