You'll get different opinions from different people...there's lots of variables and different experiences.
I do believe that APE offers solid advice and service. I think they are just suggesting that there are better, more cost effective options.
What's your budget? What are your realistic goals?
Porting, guides, bigger valves, springs, retainers, machine work for oversize seats etc. add up quickly.
You can easily drop 10 grand into an older head, once you get into epoxy work, raising the floors and moving the ports.
You might try giving SAE a call as well. They have lots of Oil Cooled experience...what works well with a current GSXR, Busa etc, doesn't all apply with our cylinder heads, you really need to find someone that worked with them back in the day...much of this knowledge is lost,
Carolina Cycle and Star Racing are other shops with lots of experience on the older stuff.
Have you already purchased the cams? Who is machining your head for the bigger valves? Are you building the engine yourself?
The real benefit of the DOT head is the floor height of the ports, they provide a more direct path. I think that would be your best bang for the buck.
However, if you've already spent money on parts for your existing head, then you're on that path and you can optimize what you already have.
Remember, it's not just a matter of throwing parts at them...it's a recipe, everything must compliment each other.
Make some more calls, research it further. It's easy to get carried away. You might just be happy enough with the 1216 kit, cams, RS40's and a simple clean up of your ports to remove the casting flaws etc.