Is it more favorable to bluff when you have big cards in the pocket and get a bad flop if you think you may be able to steal the pot? Is it almost worthless to try and bluff with low cards in the pocket?
If you're bluffing your cards are irrelevant. That is the definition of a bluff isn't it? You're fundamentally misrepresenting your hand.

At the levels I play (25NL, 5/10 SnG), bluffing stone cold isn't needed. I can't think of many cases where I stone-cold bluff at all - you need opponents who are cognizant of what you're trying to represent by your bets.

I stick to semibluffs, cbets and the odd potsteal where it's been checked to me otb. That is already plenty of bluffing.

This and a relatively TAGGy game should be plenty in the aquarium.