The diaphragms and springs can be a pain when reinstalling the carbs. At first I was scared, but once I found the right set up they were back in in no time. This is what I found very helpful.

Roll the diaphragm torwards the needle and slide the carb slide/diaphragm assembly into the carb body. The lip on the diaphragm should fit into the lip on the carb body. Now insert one of the PAIR air supply lines (about 3/4 inch) into the carb opening and push the slide against it. In this position the diaphragm lip still remains flat on the carb and the slide sticks out far enough to allow for an easy alignment of the cap and spring. I simply stuffed the spring inside the cap and held it there with a tip of a screwdriver (drilling two small holes and putting a temp retaining wire was my next step, but the screwdriver worked just fine). Install the cap and you are done.

I was also able to remove and reinstall the front diaphragm without removing the carbs. I used #2 philips bit with 1/4 wrench and found it not all that hard to do the job. Bottom screw is a tight fit, but since mine were not frozen to the carb they came out with ease.

Hope this helps.
Pawel.