I second BITSA. I ordered a pair of Deniro tall boots which come in a semi-custom. I’ve since had them for just over 3 years. I have a very slender calf, and Dover told me they didn’t carry boots in my dimension. I do not know SmartPak’s exact return policy and these boots did take 4 weeks for delivery.
I adore them. The fit was just like a custom boot. I had dreamed of Sergio Grasso’s but couldn’t fathom paying the money, these turned out to be the exact fit.
(Contact Middleburg Tack Exchange, with your size and measurements. They have a great selection, and you can find really nice boots for a fraction of the cost, even custom brands. Saddles too. Worth the drive if you’re anywhere close to DC)