i replaced my bulkhead using my existing one as a template (I know you dont have one to use)...theres a good 6"+ from the top of it to the bottom side of the deck, but there isnt an access port like you have made.
I have heard 2 different sides to bulkheads.....someone told me to seal the bow off completely...make it air tight...so it floats if it sinks...then someone else said to leave a 1/4" to 1/2" inch gap between the deck and the top of bulkhead...this allows the bow to flex freely as glass and gel flex and wood doesnt.
Here is some pics of how i did mine....i basicly replaced what was there (from the factory)....since it was an early rogers, I am not sure if its the right or wrong way to do it, but it works.
two supports bolted to the deck then glassed to the floor....
[attachimg=1]
then put in the bulkhead (it goes all the way down to the keel, but not sealed to allow water to escape) and butted the floor up to it.
[attachimg=2]