The grits you are using should give you excellent results, 2500 is plenty sharp enough for any wood working application. The scary sharp technique was my go to for quite a while and I hated scraping adhesive off of glass too. Then I started using soapy water as a lubricant for the wet dry sandpaper and found that wetting the back of the paper was enough to stick it in place via surface cohesion. Blue painters tape around the perimeter of the sheets works well too if you don't use water. I'm transitioning to water stones now but still like the scary sharp method. It allows me to sharpen 20"planer knives with a simple shop made jig and get them razor sharp with couple of sheets of sand paper butted together. You can get a lot of money tied up in various sharpening devices pretty fast so I'd advise you to pick the one that appeals to you and focus on perfecting the process. You'll find that they all yield great results when done right and that a lot of the hype about what's best is just that. Hype. Sharpening is like trout fishing. You have the purist who use custom rods and hand tied flies and turn their noses up at anything different than how they do it and then you have the guys who simply catch fish. What do you want to do collect stones or sharpen your tools? It's that simple.