Coupla comments. First, agree with Jim that twin tips are not the same as a typical flip tail. OTOH, did not read the OP syntax as "I want a twin tip," but as "if you mention a twin, please take the reduced running surface into account." So... maybe he needs to clarify his meaning, but he seems fairly, ah, open to suggestion. But then, it's probably more fun for us to reinvent his question, likes, and style.
Tend to agree with GV, mostly, on Kendo over Mantra for eastern groomers, although the Mantra will be superior in chop or trees. Also I'm 165 and have found a stiff 88-ish ski with minimal rocker is too narrow for soft snow in trees, where most of it lives, or for any trip out west, which is mentioned too. 95 - 105 is the sweet spot for tradeoffs between maneuverability and float in soft, also for do-everything trips west IMO; obviously depends on style and terrain. As far as length, a 177 at 5' 10" and 150 lbs in east coast conditions is borderline, I'd say. If you ski fast and like a boot front/tip pressure style, then yep, the right length. If you're more moderate, or if you like a more neutral stance, the 170 will make you happier. For the west, definitely the 177. Solution, for my .02, is a different ski. Something like the Dynastar Outland 87 will do better in trees, bumps, softer snow than the Kendo, 178 will work on either side of the country, gives up a bit in grip, but IME "grip" is overrated. Meaning that if you keep your skis tuned, can achieve a decent edge angle, and understand how to use your edges, most skis under 90 mm will do fine on hardpack or ice. If you tend toward lower edge angles, slide your finishes, have a more neutral stance, then you'll need all the innate grip you can buy. Similar argument to stiff beefy skis, which actually cover up as many mistakes as they create.