There are tens (hundreds?) of threads with useful and interesting info about this and closely-related models in the Forums section at Ericsonyachts.org.
As to deck stepped vs. keel stepped, either works as long as the system was designed and built properly. As far as keeping the water out, either method functions just fine, if kept maintained.
The "tie rod" is there to stop the cabin top from being pulled upward from halyard tension on the base-collar turning blocks. Some boats have it secured to the mast and some all the way down to the plate on which the spar is stepped.
If you value sailing ability, you will love the 34. It combined a nice high-end teak interior with real performance under sail -- kind of like buying a new Tartan at a quarter of the price...
When you visit the Ericsonyachts.org site, note that complete brochures and PDF's of owners' manuals can be d/l, also. All this is, of course, due to fellow Ericson owners contributing material for the last 5 years.
Best,
Loren
(one of many EY.org moderators)