This is off the cuff... so BUYER BEWARE!!!
I bike a lot. I used to go through handle grips alot. It was always a pain replacing them. I would install them wet, and it was tough, and the water would often get stuck under the grips for a long time before it dried. I started working at a bike shop. Their secret was to use hairspray. Since it was alchohol based wetness, it would dry immediately, but long enough for me to get the grips on, and positioned (and when it dried, it would add extra stickiness. Since when, I've used hairspray alot to position adhesive to great effect.
I don't know if this is common for mounting of other adhesive products, but i used it for my defender bezel and it worked great.