Any thumbrest relying on connection with the hot shoe has potential hazards because the same forces which made your rubber thumbrest come off will have a much higher impact on the hot shoe thumbrest.
Any thumbrest which is sufficiently long ( some are too short) will, somehow, improve handling but you have to be aware that they are, at least potentially, dangerous. Glueing back the rubber thumbrest shouldn't be a problem if you use an adhesive that can be applied on rubber. Silicone kit is generally harmless and you can glue rubber. You could also use Sugru and shape a thumbrest as you please. The results are generally a bit industrial but some manage to get better results than others.
Edited by milandro, 09 January 2017 - 01:38 PM.
the popular expression wishful thinking is an oxymoron!
Please remove the obnoxious tapatalk signature, it adds nothing to anyone’s contribution and it is only a sneaky way used by tapatalk to push their product by polluting each forum participant with promoting their products. They don’t even pay you for this! Nobody really wants to know about the brand and type of your phone or the program that you use to post on the forum.