+1 on bar ends
the HVMP bar ends are 17.5 oz of stainless steel, look great and kill most of the vibes coming thru the bars. They are considerably heavier than the stock bar ends, cost about $80 to Australia, but the company do seem to give us a good price when we ask( a group purchase price), or at least they did when I bought them a few years ago
I also used grip puppies, or actually some hi density foam tubing that does the same job.
I have just(yesterday) put on "grip buddies"( load this into google....
Original Grip Buddies) and I'll let you know what I think when I ride with them to work tomorrow.
but first off, I'll add to what Randy (Final Imapct)said: relax the shoulders, un-lock the forearms and loosen the grip on the bars..... bear i mind that you are sitting astride the bike and if gets away from you, and lets hope that never happens, you will not be hanging on for long however you think you have a tight hold on those bars. and I DO speak from experience there. My Bad!!!!
enjoy and remember ATGATT...(All The Gear, All The Time)