If they fit you perfectly and you dont mind them being a little soft, even with the stiffest tounge, they will be fine, however they will be no better then any other boot which fits you well and has a good flex for you.
I ride the first chair which has the 10 at first it felt like 110 flex (comparable to dalbellos ranges) but now that I've ridden it 100+ days it has packed out into the 90 territory. They have treated me well off of drops and pow.
So yeah just get a10 tongue and swap out when its pow pow time.
I have this past seasons hot doggers. They come with full tilts 6 flex, for me this is perfect for park and east coast groomes/trees. (I like my boots softer though) You can buy a stiffer toungue to switch out for powpow and big mountian though.
just noticed haha ... anyways the best boot is the one that fits you best, do not just buy full tilts becase they claim to cure all your boot fitting problems. They will only be the answer to your bootfitting problems if they fit you well. In term of flex the best allround boot is the 8 flex so maybe a seth mo or a konflict would be a better choice if you want to ride bigmountain/backcountry as well as park.
Your best bet is to go try them on with a bootfitter and see what he thinks of the fit and flex for you. Personaly for park I ski in the SPK Pro which is a 110 flex or the equivalent to FT stiffest tounge, so for me, FT do not really make a boot stiff enough for out if the park, but I ski aggresivily and im about 170lbs. If you prefer softer boots you may be fine.
i bought this years boaters and they work great in all conditions, but then again i also like flexible boots, its all preference, the hot doggers are a bit more stiff than the boaters so you should have no problems with cliffs, i took a few 15' to 20' cliffs with my boaters this season and i was fine