Sometimes, it can be difficult to get the right color reducer, and I've had to bite the bullet, or the customer does, and order from the manufacturer.
I guess if the reducer sitting on top of the vinyl made it a little higher than the wood floor, you could sand down the back of the reducer to make it to the right height. Other than that I don't know of any way to make them match up.
One important thing, though. If you use a reducer as posted in your link above, make certain the ends of the wood are absolutely flush and straight all the way across the door opening. The best way to accomplish this might be to screw a straight piece of 1x4 in the floor to use as a stopping point.
Incidentally, the type of reducer that I use negates the need for an ABSOLUTELY straight edge, as the lip will cover up the edge of the wood. However, the ones you're looking do make a better finished look. They're just usually harder to get and more expensive, so a lot of my customers don't want to wait the extra time or pay the extra money for them.
Good luck with your project, keep your fingers clear of the saw blade.