Hey there. I will make sure to give adjustments to the Brave Release mechanic, not just in terms of how powerful it is, but will also make sure that the penalty isn't as severe when losing only one life and/or using bomb items.
The manual indicates that grazing does increase the multiplier, though. It is the slowest method, however, but I'll make sure to adjust it accordingly.
Thanks for your feedback and your interest in the full game!