I've used Aluma Hyde II several times with very good results.
I conduct a thorough cleaning of the item to be sprayed. I use HOT water and Dawn OXY dish cleaner while wearing rubber household gloves. Hold the item with clean paper towels after.
Because I do most of my spraying indoors (ventilated, of course) for winter projects I obtained a cardboard refrigerator carton to use as a spray booth. I punched two holes in the top and slide an old broom handle through for parts that can be hanged. I'll use bailing wire or a wire coat hanger. Depending on what the part is, I'll improvise in some fashion to be able to spray it. For tube magazine housings I mounted a dowel on a flat board and slide the housing over the dowel. A utility lamp is clamped to the top of the box. The lamp is one of those found at Wal Mart that uses a regular bulb and has a large aluminum funnel type shade.
I use a handheld hair drier to heat the part. This is a habit I picked up from using Oxpho blue and some cold bluing products.
I've not had a problem with clumping. Follow the instructions on the can and you should be fine. Shake well per the instructions. Use several light coats. Keep the can at the suggested distance away from the part. Moving the can back and forth helps in applying light coats.
Aluma Hyde II is thick. If your spraying on an area were a tight fit of a part is necessary (such as a dovetail), you may want to spray lightly in that area. I've found the product to be very hard and durable. A light coat in such an area should be fine. I've used that practice in dovetails, tube mag housing on .22 RF's, inside receivers, etc.
Aluma Hyde II will dry to the touch in approximately 15-20 minutes. Brownells reports that it takes a full week or so to fully cure. I've always adhered to their advice before field use. I will continue working with the project, however, after an hour or so.
Just as with many sprays, when finished spraying, turn the can upside down and spray until just compressed air comes out. This will clear the nozzle. I did order an extra bag of nozzles with my first can, but have yet to use any.
Hope this helps. Good Luck.