The blow gun trick works slick for getting your old grips off, and they can be reused...
To re-install grips, I use black spray paint. Spray the bar ends, the last 4", slide the grips right on. They will slip on easily. Leave them sit for an hour, the paint dries and cements the grips to the bars. Done lots of them this way. Just hold a rag or paper town in the had you are not spraying with to catch the overspray as you go. I would imagine the hair spray has the very same effect, if the wife has some! We all have black spray paint in the garage, don't we?
Oh, and when you put the new heaters on the bars, make sure you orient the wiring so it does not interfere with the switch bodies and throttle lever. You also want the elements to be where your hand will be, with the bulk of the element on the front side of the bar where your 4 fingers wrap around. You only have one shot to get it right: lay the elements on the bars, see that the wiring won't pinch, draw its outline on the bar end with a Sharpie. Then remove the sticky tape and put it precisely where your mark outline is.