Good observations. Hooker "Comps" are smaller than SuperComps, true enough. If the 1 5/8" tube is "big" enough for your application, they're probably the best bet. And Tom is right. Hookers ARE very well made.
The long branch manifolds are infinitely preferable to "shorties" Shorties are for "bragging rights", not power production. Factory cars in later years use them because they're both cheaper and make more power than the cheesy Chevy exhaust manifolds.
For those not familiar, you might want to talk to Mark at Mad Dog. They're relatively "new" to the industry, but LIKE Pontiacs.