I am aware this topic has been discussed over and over and most charter websites touch on it as well but I still have one question, is the suggested gratuity per person, per cabin, or per charter?

For example (from TMM)
WHAT IS THE TYPICAL GRATUITY?

Skippers work hard to provide the best possible service to their clients. If they have done a good job for you, they will appreciate a gratuity at the conclusion of the charter. A rule of thumb is $350-$500 for a one week charter. A one-day Check-Out Skipper (COS) gratuity would be a percentage of the fee of $175. Twenty-five dollars tip for a COS would be a good rule of thumb. All gratuities are optional.

Is that 350-500 per week per person, per cabin or per charter?

Others sites suggest 15-20% of captains fee, same question applies.

Thanks in advance!