Stephen;
I converted my 1978 IOR 34 from a tiller to a wheel. It was not easy, but it was worth it to me. I used the Edson CDI system, with an arm on the rudder post and a drag link to the pedestal, and a 44 inch wheel. The previous owner raced the boat extensively with the tiller and was shocked by how much of the rudder feel was still present in the wheel.
The CDI system comes with a built-in brake in the wheel hub. While single-handing, I have actually used the brake to lock the wheel and steer the boat while I went up to the foredeck to change sails. The brake will hold the boat on course for more than a half hour if sails are trimmed right. I could never accomplish this by lashing the tiller.
The usable space in our cockpit is greatly increased with the wheel, and it's a lot easier to see the crew, sails, and what's going on. tacking is much more pleasant as I watch the boom swing in front of my face rather than hitting me on the top of the head as I ducked and switched sides with the tiller.
Issues (Cons) that I had with the conversion were:
The scuppers interfered with where the arm needed to be placed on the rudder post. I had to re-route it - which involved sawing through the deck and re-glassing the port side cockpit dran area.
Edson doesn't make a engine throttle and clutch control for the CDI system that will operate an Atomic4. Until I relocate the engine controls, I have to sit on the starboard seat, in front of the wheel, with my left hand on the wheel, and my right hand on the throttle. Relocating the engine controls from forward in the cockpit to put them behind the wheel will be a big, fiberglass-infested project.
The cockpit was not completely symetrical. Even though I very carefully positioned the pedestal in the center of the cockpit floor, the large wheel interferes with a 10" winch handle on the port sheet winch - I have to use an 8" handle. The starboard winch is fine.
Cutting the large hole in the cockpit floor was certainly intimidating. It was necessary to grind the underdeck back and glass the entire circumference to encase the balsa in the deck.
The wheel system only added about 12 lbs. to the boat, but when I position myself behind the wheel the balance is effected. In light conditions, I have to steer from the side or front of the wheel for optimal performance.
Drilling the 1/4 inch hole through the typically Ericson over-designed stainless steel rudder post took me three hours with oil to lubricate, water to cool the hot bits, and several different expensive carbide bits.
The conversion was expensive, but mostly becuase I chose expensive options. My 44" wheel cost three times as much as a 20 inch wheel. The CDI system is 1.5 times the wire rope system. Also I had the arm on the rudder post shortened. These three options give me the rudder feel I wanted to preserve.
In the end, I like the boat quite a bit better, and it was a lot less expensive than trading up.
Good Luck with your project.
Steve