I've already told Andrew this, but others might be interested. A friend of mine used the Canon 100mm focusing unit with the Sony 90mm with the 130 and 100 objectives with no apparent issues. 
 
	 
 
	I suspect that all the focusing units might work with all the listed lenses with the only difference being that if you're using a focusing unit designed for a longer macro you'll get a slightly wider FOV and vice versa. There is also the possibility of vignetting when going wider, but we won't know for sure until it has been tested. 
 
	 
 
	I have been interested in trying the Nikon 105mm focusing unit with my Sony 90mm to see if it increases the FOV but haven't had the opportunity so far. 
 
	 
 
	John's setup (90mm focusing unit with 105mm lens) should provide a slightly narrower FOV.