Street Twin Gearbox Protection Washers?

So having read that the Street Twin gearbox is vulnerable to damage if dropped due to impact on the selector shaft I looked into what could be done to protect it. I have the R&G crank case slider, but that probably doesn't stick out enough despite being told by the salesman at Motorcycle Live that it would. Seems like engine bars would likely not stick out far enough either. So I have decided to do the washer protection that some have done. The idea is to pack the gap between the gearbox case and the lever with washers. This prevents the shaft from being driven into the box and also reduces possible bending forces from the peg on the gear selection lever hitting the ground. I have ordered some washers;


Which combination to use though? I am leaning towards nylon against the case, with either the the two stainless or single thick stainless next to the lever, depending on best fit. All options would be greased. Any thoughts, or cautionary advice before I get stuck in would be welcome.