If the clicker bothers him, you could try a retractable pen or a baby food jar lid (or some other lid with the "pop-up" in the middle). These are usually softer sounds than the clicker.
You might want to sit down and write out a training plan - it will help you set criteria and decide when to move up or down or stay the same. (Generally once the behavior is 80% fluent, you move up.)
What exactly are you doing? Are you luring or placing him into a semi-stack, and then wanting him to move his back foot into the proper spot? If that's the case, I'd start small - click/treat for moving his foot - once he's consistenly (80% of the time) moving the foot, only click when it is within <<some area>> of where you want it. When that's 80%, decrease the area until you're getting the foot where you want it. Then (and this may be harder) work on him putting the foot in the right spot to begin with.
The way I did it (just for comparison, you have to do what works for you) was to keep a clicker and treats handy, and without specifically working on a training session, I would click and treat whenever her back feet were in a good position - just as she was standing around. That only worked a few times, of course, because then she wouldn't go away and stand somewhere else
So then I worked on her standing in front of me, getting the back feet correct. Not *precise*, but within a paw's width of where they were supposed to be. Then I worked on the precision, only clicking precise placement. Once she was good with that, I focused on the front feet - just moved around, had her stand in front of me, and when her front feet were good click/treat. Then more precise - again within a paw's width. Then I worked on precision again. Somewhere along the way I built in "hints" - extending my right leg toward her to have her re-set her left rear leg and vice-versa. For ears forward and up on toes I did bait a little at first (this was the first time I actually used food as a lure instead of just a reward), which actually helped to develop my hand signal anyway. Now, a forefinger held up is her cue to stack, and I extend my arm down and slightly behind me for ears forward/up on toes.
If he's going nuts over the treats, keep doing the Doggie Zen, and try not having the treats on your body when you train. Have them in an out-of-reach bowl nearby, so that you can still treat right after you click. Or try a lower-level treat - but that might be less motivating/reward, too.