Four strokes beat up these model's structures pretty well, so two strokes would be more applicable. Both from the pounding and the weight. A bushed 61 or BB 46 would be the proper weight for the Taurus as described above. A friend has a good flying Astro Hog with an OS 61 SF.

If you're going to use those YS engines, I'd go for the smallest for the Taurus and the bigger one for the Astro Hog.

Chris...