You can't buy the saddle until you find your horse!! I know you like TB's and let me tell you how many I went through trying to fit my boy. Once you have a horse, you can look for saddles, if it doesn't fit him right, you'll be stuck with it!
I have an all purpose black 16.5' wide tree english saddle with knee rolls. Comes with irons, girth, leathers, and four pads. Asking $250 OBO. I havent measured the flaps...if you are interested, email me at [email protected] for pics of PM me your email addy and I can get them to you.