Without seeing pictures I would suggest a stop! The cab sounds like you have a lot removed and even braced this requires some planning. Panels are not going to weld in like they came out. The factory used a majority of spot welds on these cabs and they were constructed with ease of that in mind. You will have to determine the joints and areas to weld. The rear cab structure is difficult for full panels because of how it is constructed but I would advise not cutting any more until we can see pictures. There are some real good body and fender guys here that can help.

If you look on the Forum List page you will see one called the IT Short Bus (near the bottom) it has directions on options and how to post your pictures.