I'm drawing up a design for a 2 cylinder unaflow scotch yoke engine, about 1" bore. My goal is efficiency and simplicity. I know there are good argument against the scotch yoke, but it reduces moving parts substantially, and with good design of the yoke "follower" (?) I think wear can be minimized. I'm thinking that in the scotch yoke horizontally opposed format, the gas-spring effect of compressing residual exhaust gas would protect the yoke from shock. But I do not want steal excess energy from the system. I'd like advice about piston/cylinder geometry. I'm imagining a long throw would be good in a scotch yoke, as it might extend expansion time and reduce required valve speed. But it might also result in higher pressure at TDC. I guess it *could* be higher pressure than inlet steam pressure? Any comments gladly received, thanks.