Madness! Sheer madness!!

Albert
Yes, That is one thing I had noticed over the last few years or so since I caught the steam bug is the use of Stephenson linkage on damn near everything steam powered. I never could get a straight answer for the reason. Was it the best and most efficient or just the simplest way to go? When I found steam engines that were designed for efficiency like some found close to the end of the steam era they had major tweaks to the valve linkage making it easier to control inlet timing. Then the Corliss engines were said to have far better efficiency ratings and actually had no Stephenson linkage at all.
Now that I understand more about how steam behaves I understand better why the Corliss linkage is designed the way it is. Which puts me more firmly of the opinion that I will look for a more variable method of valve timing, not just the simple one.
As far as high-pressure flow cutting valve seats goes, that can be solved easily with the right valve and seat material for the job. I had in mind using the replaceable seats from a high-pressure paint sprayer. I don't know what they are made of but I cannot scratch them with anything short of a diamond blade.
I have pretty much nailed down the displacement of each cylinder, the stroke, the crank size and bearing types. So at the moment I have been looking at various valve timing arrangements and there adjustability. I like the look of the upside down Pearl Engine but am a bit leery of the big end rod setup. Does anyone run one of these engines? Is there a Pearl compound and have there been any problems with the wishbone shaped rod?
Cheers
Scott