This is a great texture gun when dialed in right. Unfortunately, the instructions are not much help. Fact is, every situation is different and the manual doesn't really spell out what to do.
First off, you need to prepare the ceiling. A quick scrape with a 24" trowel will get help get rid of some grittiness. It is highly recommended that you prime the ceiling before texture application. This will help homogenize the surface. Meaning, that the drying, coloring, absorbing, etc. characteristics of your various ceilings throughout the house will be normalized so that they will be consistently the same throughout. Baths and kitchens are usually the most extreme in variance, because they usually receive more paint coats over the years (not to mention repeated exposure to higher humidity). Therefore, without priming, the drying time in particular will be much different in the bathroom than it would be in the living room. Priming will help to normalize your overall drying times and make a more consistent overall texture.
Second, forget the book instructions on how to mix the mud, set the gun, and set the compressor. For a new construction, they may get you close. But, in a remodel situation, the recommended settings wont work. Your best bet is to buy a sheet of drywall (prime it first) and try out several mud viscosities, gun settings, compressor settings, tips, etc. For our application, we found that 50-55 PSI at the compressor, 1/2 to 2/3 flow at the gun, 3/4 throw at the trigger, and the medium tip to work best. Mud mixed to heavy cake batter.
We have a 150PSI 26 gallon compressor, 75 feet of 3/8" line. This compressor was way more than enough for this job, so if yours is smaller you should be fine. I would probably stay away from a cheap 3 gallon compressor, though. 125PSI 10 gallon compressor is probably the lowest you will want to go if doing a whole house.
Once you get your setting and equipment dialed in, you will need to develop a strategy. Smaller rooms tend to dry slower than larger rooms. So, you may want to do those first. However you do it, you will have to judge each area individually before you use the trowel. Don't just rely on a clock. Some of our rooms were ready to trowel in as little as 30 minutes, while others took about an hour. Practice on the test drywall sheet until you can get a feel for when to trowel. Once you get that down, try to trowel in a consistent motion. I found that a 24" trowel worked best for us. It allows you to work the smaller areas, but also has a great spread in the larger areas.
After texturing, allow 24 hours to dry. Use the trowel again to remove bump and grit. Next, you need to prime again. This will normalize the ceiling for painting. Paint and you are all done.
Conclusion, practice and priming are essential if you want a professional look. It is a ton of work to do this, so be prepared to spend 3-5 days minimum for a whole house application. In the end, you will save thousands.
Performs Well, Good Size & Weight, Great Value, High Quality, Economical