Just finished mine a couple of weeks ago, but with work etc, I've only got three flights on it...well 2 and a bit flights...I had one of the older guys, pardon me, "more experienced"
guys do the first flight...I did fly it, but he took it off and landed it.
Yes the turtle deck is sheeted. You have to cut the pieces for it from the sheets in the box. Mods I made were to move the main gear ahead about an inch, dual servos for the ailerons(easy to do since the instructions/kit came with all the extra bits) and a Sullivan tail wheel. Mod I wish I had done was use a size or two larger blindnuts for the main gear to allow for using larger nylon bolts.
As for how long to build...I can't give a good answer...with work etc, I'm a slow builder...but remember, with two wings to build, it will take longer!
If the weather is OK, maybe I'll get another flight in on it this weekend!