I can't remember the cost of the retracts but they are more expensive than $75.00 Here is the link to the web site
http://www.retracts.com/
The nose wheel is slightly bigger than what they recommended (for better angle of attack on take off). The mains are exactly what the plans said. I can't remeber the size but they fit in the spray can top wheel wells that are installed in the wing. I live in Canada and the grass is less than ideal and it doesn't have any problems. Don't worry about it and go fly.....