I need some advice on the correct/best layout for building a window jamb extension for an unusual shaped window. Everything I've read, for a typical square/rectangle window, the horizontal pieces are cut to the full length of the window and verticals are cut a bit short to accommodate the thickness of the board that they "stand" on. I have a window where there are three windows installed as a single unit. The middle unit is taller than the two edges so it has the appearance of steps. Something like this _______ _______l l________ l l l l My question pertains to the two corners that are the reverse direction from what is in a typically found in a square/rectangle window. Do I continue with the pattern of the vertical sides "standing" on horizontal pieces and thus extend the boards that are at the top of the shorter windows past their edge so the short verticals on the higher portion can stand on them? Or can I extend the verticals on the higher window down and attach the horizontals to the side of those pieces? I'm not sure if the typical board placement is constructed for a structural reason or an aesthetic reason and want to make sure I'm not messing it up.

I have a cabin in northern MN that needs the original windows replaced. They are Marvin casing circa 1982. I know very little about building materials/supplies but have typically made purchasing decisions around cost for the most part. The more it cost the better it is or could be. I KNOW not the best approach but that is me. The cabin is used minimally in the winter so hardcore MN thermo protection is not priority 1. I want to move away from the casing windows for the sole purpose that they hang out to far as many of the windows are on the deck. I prefer the sliding windows. Here is my question. What are your thoughts on Walsh windows out of Duluth. They seem to be a good value but again IDK much. I'm ok with the vinyl vs. wood although wood does look better but do please give me your thoughts. They will be whole replacements & when looking at the Walsh site it appears to me that the frame/trim is a bit wider. This is a hand scribbed log structure that has been in place for 40 yrs so the settling is done. My hope is to simply take the old Marvin's out, square it up/adjust if need be & install the new units. I prefer to not make the opening much wider but a bit is acceptable. Probably not using the correct terms but I think you may know what I mean. I'm 52 so the next time the windows need replacing I'm hoping to be on the deck with a scotch/cigar watching my now teenage kids do the work. Any and all recommendations are welcome. I do know the lead time for Marvin's is very long. SAD! Any other brands? Price is a consideration. Thank you for sharing your experience., Experience I do not have but want to learn.