With the hooker mounts and headers, you don't have to cut out the hood latch. With jtr, you've got to cut out the 45 deg part to clear the distributor. I'm not sure about msa.
The hooker mounts position the motor pretty high, and air cleaner clearance is very tight. You see a lot of hooker cars with the little foam air cleaners on them.
I use the jtr mounts because you can wind up with an almost 50/50 F/R weight dist, about 52% on the rear with me in the seat. I do road race track days and time trial my car, so handling is important. With the hooker setup, you're probably going to wind up 54 -55% on the front. It's not the end of the world, but it's not optimum for handling. For a nice street car, it probably wouldn't be an issue.
There are a good many compromises made in a project like this. Set your priorities and name your poison.
And yeah, Secondhand Lions is a masterpiece. One of my favorites.
jt