I completed conversion to wheel steering on my A28 during summer 2004. It took me a long week end to complete everything, and I am very happy with the result.
I bought all the conversion parts from Edson through a Canadian dealer. Edson has a recommended parts list for the Aloha 28 already and it is basically everything you need. The only things I had to add myself is the support for the ends of the conduit on the transom side, and ply wood to strengthen the cockpit floor. The key thing is to determine where to put the pedestal on the cockpit floor and whether the recommended conduit length ( 5ft) is enough. If you need longer conduit you have to order longer cable. Edson is very helpful but may not know enough about the details of the Aloha.
Getting the quadrant through the hole cut on the transom is also tricky, since you don’t want to cut a hole bigger than what is required. Designing and making a hood to cover up the hole from rain and water and still allow normal movement of the rudder is not easy, but do-able.