Yep, I find Ernst plates not only makes it convenient and fast to set right or down thrust angles, but they also spread the stresses evenly on the firewall and engine mount. Washers tend to get pressed into the firewall after some time due to the high vibrating forces spread over a tiny area, and is a safety concern. This will cause a drift in the thrust angle. A set of Ernst plates cost less than a couple bucks from Quantum.