Get 3 or more razors you don't mind scratching up, maybe the Lord L6 since they are cheap and L6s usually have consistent blade alignment. Load each with a blade you are trialing, and throw them into a bag and shake them around. Pull one out and shave with it until the quantity is exhausted.I've been thinking about how to accomplish this, because I think that we will be very surprised at the results if we did conduct blind blade tests. I have not figured out how to make it happen and I am talking across several wet shavers.
That's probably how I would do it.