In the absence of advice, I've decided to switch to 1x6's for the frame so that I can make the sill out of two 1x's. One 1x will complete the frame, the second "finished sill" will make an extended shelf. I'll use quarter stop for the jamb portion of the frame and the "finished sill" for the stop on the sill.
For the removable sash, I've decided to use 2x2's. I'm going to gato the lengths of 2x2 to accomodate the glass (double pain... pun intended) and, maybe, run them through the radial arm for a bevel. Silicone to seal.
I purchased a used vinyl window for the glass. I can use the locks off that window to hold my removable sash.
I'll post pics when I've completed construction which will be this week.
Last edited by AlwaysOneMoreProject; 11-06-2010 at 06:56 PM.