I have eight blocks. If I need to take off wheels, I just put the blocks under the jack pads points by lifting from the front cross member, differential or factory jack holes with grade eight bolts.I have looked at the idea of using blocks like that. But as I want to bleed the brake system while I have it up, I've been looking to take all 4 wheels off at one time... Setting tires on boards doesn't seem to be compatible with that idea.
One advantage I found with blocks is that I can safely work on my sloped driveway if I need to. Changing fuel related items is one example I don't want to do inside the garage.
Whichever way you choose, be safe.