You might find the health tips link helpful- (transitioning off dry, etc) sorry if you know that stuff already, but if you are nervous, knowledge is power:
viewforum.php?f=14
As for the food, you can feed the canned Purina DM. The new formula last fall (silver top cans) has 5% carbs and it is very dense, so you get more food per can than any other food I've used. I do add some other high quality protein to supplement the liver as the main ingredient, such as chicken, (egg and/or salmon). You will use less insulin as soon as you get rid of the dry, so you are going to need to keep a close eye on that with regular testing while yo transition away from the dry.
Prozinc is easy insulin to use, but as with any, you will do better if you test a lot so you know what is really happening through the course of the day.
The stickies at the top of the forum talk about typical duration , nadir, and onset for Prozinc, but of course every cat is different.
The strips for the alpha trak are pretty expensive aren't they? You might want to consider a meter with cheaper strips so you can test more often. Relion from Walmart or Maxima from Hocks (Green link above)
Once he gets off the high carb dry food he will likely lose some weight automatically, so I wouldn't restrict his wet food at all. Cats can't really use the carbs, so they turn to stored fat.
Are you home during the day to get mid cycle readings? If you are planning on shooting before 12 hours, the main thing with PZI is that the numbers are clearly rising (like 30+ points) before you dose again. A few folks had luck shooting 3x/day at approx 8 hours apart. I found this difficult, because many times we weren't at a shootable rising number at +8 hours, and next thing we knew he was due a shot in the middle of the night :? :sad:
Welcome and we will help as needed. just ask