I just bought a 1987 Irwin 38; sits in Herring Harbour South right now and will be home on the Magothy this coming spring.
I hear ya on the traveler, mine needs some revision on location and how it works. But seriously - boom end traveler's are far better, and putting it on the bridge deck will seriously compromise the ability of the traveler to control the sail - it's about arc and how much travel you can get from the traveler.
Here's my setup currently (as bought):
For those non-Irwin folks reading - and me, I'm assuming you mean to put the traveler up on the forward coaming (next to my coffee cup in the photo).
That also means your mainsheet would be mid-boom - and all that tangle and mess of lines has to come back to the helm.
My revisions will be to replace the pin stop car with a 3:1 sheeted arrangement - then have the control lines go off to either side to a turning block with a cam cleat - simple and efficient way to get the lines into the cockpit where they can be adjusted with one hand.
I fully believe that the traveler should only be centered when motoring, I use the heck out of it to balance helm and heel control.
I'll be watching for your posts on the deck core - PM if you are close by to Pasadena, Love to have a look.