Michael,
I am restoring a Lotus Elan +2 and have recently bought a new Motolita leather rim. They (Moto Lita) still make wood rims. Have a look on their site and/or phone them. They're a good bunch of guys and'll let you know all about the steering wheel. Four holes in the spokes is probably something to do with the diameter of the wheel. My wheel is 14" dia and has
3 holes. Moto Lita were a cult steering wheel in the 60's and 70's and still command a lot of respect. Very classy. Today a new wood rim is probably about £140 + £20 for the boss. Hamish.