Bone vs. No bone Ribeye

I have done both. Only difference is with bone in I place the bone side down. As far as time, I would think the bone  in would take slightly longer based on the increased mass, and insulation the bone provides, but I dont remember it being majorly different. 

Usually I like basic flavors so I mix s and p, garlic salt, little onion powder(use sparingly). 

If I have time I marinate in 1/2 Worcestershire 1/2 kikkoman soy sauce (it tastes the best to me), little minced garlic. Do it overnight. Gives killer flavor to the meat. 

Thats my two cents.  

I have cooked plenty of 8-10 pound bone in ribeyes (standing rib roast), but never that low.   I always cook them at 375-400F, so I can't advise on how long it will take.  

I can tell you this, believe me now or believe me later, I would never attempt to cook one without a remote thermometer ($20) to continuously monitor the internal temperature of the rib roast.  I take them off at 112-115F internal temperature, and they always run up at least 20 degrees while resting. During a 30 minute rest, they run up above 130, which is higher than I really want.  I think if you are cooking at a lower temperature you will get less run up, but hard to say how much less.  (My guess would still be at least 15F.)

First time I cooked one, I ruined it thinking that the time estimates meant something, 10 pounds of medium well rib roast.  I had a table full of disappointed dinner guests, and had basically wasted over $100.  It's not about time, it's about temperature.  

Hopefully someone has cooked one that low and can give you an idea of how long it will take, just for planning what time to eat.   I still strongly recommend a continuous read thermometer.  $0.02.