Billy
You are spending way to much time overthinking a simple deal,,,
When it comes to seals
Brodix is primarily a drag race company so it errs on the safer side of wide open throttle operation
If this is what you do not having seals on the exhaust is usually a good thing
In street usage as Jason stated earlier in this thread if you are cruising at say 3000rpm under no or light load conditions you will likely want exhaust seals
The reason is both simple & intuitive if you give it some thought,,,
Under these conditions you have both low pressure & a "siphon" effect in the exhaust port
Ever use a siphon gun to clean something?
What happens when the air passes an orifice with a liquid in it at a fairly steep or right angle?
Same thing happens at cruise to the exhaust guide... if you develop a low pressure area under the guide the oil is going to head there unless something controls it
Enter the exhaust seal
To another question Brodix usually uses the exact same metal encapsulated Viton seal I have been using for longer than I can remember
See Rick's picture above, excellent shot of the seals,,,,,,,,
With the exception of extreme lift or less than normal installed spring height (shorter valves) They do not need any machining to install on any aftermarket head I know of, they have an interference fit to the guide (this means they are tight around the guide)