There's one advantage to processing watch bands that is often overlooked. The vast majority of their construction is stainless steel, which is not dissolved by nitric. You may be able to process by a nitric digest, which will eliminate non-ferrous materials, leaving the gold behind. Problem then is to separate the gold from the stainless. It will be trapped in all kinds of ways, so that may not be as easy is it sounds.
By applying AR carefully, you may be able to reduce the amount of stainless that remains with the values. Less than would be required to dissolve everything is applied. Values dissolve, then then they are cemented on the stainless, dissolving the stainless in the process. When no values are detected by testing with stannous chloride, the solution is siphoned and the process repeated. When just traces of stainless remain, everything is dissolved and processed for recovery of values. It requires patience, due to the slowed recovery of values as the stainless diminishes in volume. By this process, the vast majority of contamination is removed, yielding a better quality of gold, and from a reduced volume of solution.
Alternately, you can pick off the gold filled pieces, discarding the stainless. That works perfectly well, but you must look at your time as having no value. Fine for the hobby refiner, but certainly a losing proposition for the guy that values his time. Watch bands tend to be a rather poor source of gold (but still worth processing).
Should you make a decision to process by acid, make damned sure you incinerate the watch bands. You'll come to understand they are filthy---loaded with soap scum and body oils.
Harold