Hey Mike ,
yes my method is much easier for a 90 and under size model . I bought the more expensive rails and even used my method on my CMP Fw190 bash .
THe reason is that you dont have any flex on the rails , so instalation has to be perfact . The simple method we used allows flex and fixes problems if the angle is off , unlike the rails that need to be perfact .

I like the pics used for the corsair , but on the KMP that would mean I need to cut a slot into the rear fuse , and i dont think I have the thickness needed without adding a wood internal support plate . Also the part that attaches to the canopy(shown in the picture ) is custom and not part of the purchased rails

I left the P40 as non sliding , I am going some final pics with weathering soon , I just need to get it done so I can move onto the FW and then start the winter project of the KMP corsair . I plan on major mods on that one including a full scratch build interior