I can help a little. When your chopping a top you have to take into account the angle of the posts. on early cars the post are pretty much straight up and down so it doesn't matter as much. On later model cars the posts are angel ed so as the top comes down it needs to get wider and longer. You'll wand to mark all the posts and make horizontal cuts taking the same out of each post. You also need another top that has similar curves. I glue the four corners of the top to the posts then fit and glue in the extra roof parts, I use a file to flatten out the joints then putty and prime.
Here's some basic tools you'll need.
Cutting open doors I put masking tape on each side of the door line to protect the body while cutting. I use the back of a #11 blade and just drag it around the door opening till I cut through.
There are better guys at hinging doors to help there