For being rewarded for bravery - I cannot recollect in my studies finding a source that showed this, at least for my period of interest of the 1680s-1720s. There were other rewards, such as some crews providing rewards for spotting a potential prize ship first (sometimes it was money, other times it was the best pair of pistols found onboard the prize). But for "bravery," haven't seen that expressed in period documents (especially not in the articles the pirates ran their crews by).

As for the other question of captains and shares, the greatest number of shares is Captain Kidd. When he drew up articles with his crew after turning from privateers to pirates, he received five shares for being captain and thirty five for ownership of the ship they used. Why did this crew allow so many? There are several potential reasons. First, it was not absolutely unheard of for captains to receive five shares. The captains under Henry Morgan in 1670 received this many. When navy captains and privateers of this era took prizes, their shares were even more than five. It was not as if there was no precedence for this in the maritime world. According to Dr. Ed Fox's thesis concerning pirate articles, other potential reasons for Kidd's large share may have been due to Kidd leading the company, "into piracy and retained command in the process, thus giving them a certain natural authority with which to back their claims to excessively large shares." This also explains why he received shares for owning the ship. Also, Kidd's crew may have, "operated entirely removed from the influence of other pirate companies at the time the division of shares was agreed, and so escaped the influence of the spirit of financial egalitarianism that pervaded other pirate companies."
It's hard to nail down one exact reason for Captain Kidd, Kidd being a somewhat unusual case in pirate history during that era.