From what I recall the Byron Glassair was designed around the G38 and Quadra 41/42 engines . I saw a couple fly on the G38 and it was scale like but no not much reserve power . Now the DLE 30 out powers the G38 by a bunch so you can draw your own conclusions from that . I myself would go for the most power I could fit in the cowl and keep it scale looking maybe a DLE 35ra or a nice twin if it would fit .