David, I assume you are adding hotmelt for weight? Is that correct?

If so, I would consider buying a Titleist Hybrid weight kit or lead tape to make adjustments. It works for me without any problems!

Chris, thanks for the reply. You are correct, I am adding the hotmelt for added weight. I intent to change the weight from the standard red color code to the black color code however the hybrids (19 and 23 degree) with the Speeder HB8.8 shaft and golf pride midsize grip came in with a swingweight of C9 and D0, respectively. I am trying to get the swingweight to a D4 so I don't think simply changing the weight will get me all the way there. I would typically just add lead tape but wanted to consider the pros/cons of using hotmelt and was curious if others have done this on the 816 hybrid heads and what their thoughts/experiences were.