Instaling windows in a very old house

I have a very old sliding glass door from the 70's that has a broken latch/handle mechanism. I found the exact replacement handle here: [URL=http://www.allaboutdoors.com/product_info.php/cPath/74_80/products_id/14045?osCsid=ee4ef98a6368ea0308c3f2a4fca0fead]Latch[/URL] I would like to update the style to something more modern. Am I stuck with this style latch? The only thing I can think of is to buy the latch, cut off the "retro" part of the handle and buy a set of handles like [URL=http://www.allaboutdoors.com/product_info.php/cPath/74_80/products_id/1278010?osCsid=ee4ef98a6368ea0308c3f2a4fca0fead]this[/URL] to attach around the mechanism. I'd like to do this as easily as possible and not have to do too much cutting but it seems as though the only option is to use the original style latch.

Hi We recently bought a house and have decided to open up a wall between a bedroom and the living room. We want to put a set of french doors between them and went to the hardware store to see what the deal was. The units they have in stock are just the door panels with no hardware such as hinges or flush bolts installed. Also, they are not prehung so the jambs and what not would have to be installed and assemble by me. How difficult is it to do this work, I have access to a router and most tools and I can work through just about any project. My questions are, how hard is it to mount these doors to the jambs? How hard is it to install the hardware like hinges, jambs and flush bolts? Is it difficult to end up with a good finished product that is square and nice looking?