Optimum is designed for plastic ball.
When you paste with that glue, your rubber become a little bit hard, this is the reason why it’s appropriated for boosters too. It allows you to gain the hardness you loose with the booster.
Its texture looks like liquid cream so thicker than the water glue 10’ which looks like more than water.
Put the glue onto the rubber and the blade. Let it dry until the glue become transparent. Assemble the rubber and the blade. Put 2 layers for new rubbers. Appropriate before use booster and after in order to glue the tuned rubbers. Affected by frost.