Ahh, I see what you mean now.
I think I'd prefer 6789ds as you are more likely to make a hand you are happy to go all the way with.
not necessarily - i'd still be very catious if i hit my flush as its likely someone would have the higher flush, the same if i had the low end of the straight draw (for instance on a 9-10-J or 10-J-Q flop).
Obviously the only hand your safe with is something like 3-4-5 or 4-5-6 rainbow.