I'd be choosing the longer focal ratio for a doublet-(for colour correction). That's why I chose the M90 at F6.9 over the M110 at F5.9 or M88 at F5.8. If you have enough spare for the triplet, I'd certainly get the WO FLT 110.and chose the shorter focal ratio. But I'm happy with my WO M90 as it does double duty as guide and imaging scope on the LX200-ACF. And its a great grab and go scope for short trips to the country.