Vampire Player Character System, Not "munchkin"ing, just want some advice Options

[JudgeIto78]

Ok, I have a GM who is just crazy enough to let me be a Vampire PC and we, of course, referenced the Critter's Guide for the description of powers and such. Anyway, this is what we have come up with so far relating only to the question I will ask in a moment:
1) Must drink blood twice a day
2) Will lose a point of essence every two weeks
3) Can only have up to double essence (with no cyberwear = 12)
4) Enhanced Physical Attributes (Str, Body, or Quickness) with increase to chosen attribute by current essence and activated at will only twice a day.

#4 is the part at issue. My GM and I were wondering whether there should be a limit at all and should it be based on rage and animal instinct instead of as listed above? If so, should it affect ALL of the attributes and should it cost essence for me to do it (simulating the energy spent to be in a "bloodlust" state)? The reason we are bringing this up is because I am essentially taking in more essence than I'm losing and there is not much reason for me to "drain" someone during a mission. This proposal would force my character to have to feed in order to fuel the abilities as noted.

I know this sounds like "blood points" from WW Vampire and I am familiar with that system, but I think some essence loss is more appropriate than only being able to boost one skill a limited amount of times.

Any thoughts would be helpful and thanks in advance.