I don't believe that there is a "drop seat" feature.

I used to work for Wolverine World Wide, who produces Merrell, and their apparel has a tendency to fit tight. I'm 5'10" 170lbs and usually wear large in Merrell. My guess is that you are right between sizes. I'd go with a large however. The XL's from this company seem to be designed for people with large bellies. There is also a post below from a 6'1" 190lb person who claimed it fit well with layers and everything. My biggest concern would be sleeve length, so it ultimately depends on how long and lanky you are!!

It's hard to determine what size you would need without height and weight. They have black S-XL at the moment. My guess for the size of the jacket would be a L basing that on an average 13 year old size. I believe they can mail to France using the global shipping information.

The summer kit is not closed cell foam, so would probably not be the best for water sports. However I wear this helmet for skiing and it rules.Overall, if you need a hat that has more bang for your buck, there may be better options out there for you.

Having sold this jacket at a retail store, I would recommend the small. Most people find that the XS is way too short for their torso. If you want a down jacket that fits more like a belly shirt get the XS in my opinion :P

This is more of a waist (or slightly longer) length jacket. I wouldn't recommend it for covering your butt. You might look into a Patagonia Powder Bowl Jacket for that. They are on sale on their website at the moment for $210.

The pack itself is nylon, and is not waterproof, but either are the zippers to be perfectly honest. "Waterproof" zippers are very water resistant, but not 100% water-tight. These types of zippers and pockets will help keep gear like your cell phone or wallet from getting soaked in a sudden rain shower. That said, I'd recommend a pack cover for a truly waterproof solution.