I think maybe you should reread my post. I said nothing about bottom end- the midrange and highs have been my issue. I always start with a zeroed out eq, not sure why I would start with anything else.
I'm of the opinion that less is more. If I can use a mic that I have to do very little with by way of EQ and still sounds great with predictable results then why am I going to choose the other one that's apparently a science project every time it gets plugged in? If it's so damned outstanding why doesn't it sound better without an eq? Oh, right, to prove how good we are at using EQ's!
I have no doubt that Bob H is as nice as they come, and I truly have the utmost respect for him. I just haven't been that enthused about what I've experienced so far and no one has seemed to offer any worthwhile suggestion on what I'm doing wrong or others are doing right.
And Bob L- why don't you share some of your super duper trade secret eq curves or some kind of suggestion other than "start with a flat eq curve". Surely you must have some trick up your sleeve if you're using the PR35 90% of the time and when you're "not feeling lazy" which seems to suggest it's work for even yourself to make them sound right.
I actually read your post three (3) times Ryan, and to be honest, with no mention of an external system EQ or DSP of any type I wonder if you actually understand "flat". If you want to work with different mics then try to EQ your system to a point where the system is flat first. Then and only then will a flat channel strip have any realistic meaning.
I read where you use an SL24 and I'll assume you're using a Carvin SL24. My experience with those boards leads me to think you're doing nothing really wrong, other than maybe using that board with a system that's not tuned properly. To my ear they sound very clouded regardless of the channel strip EQ settings, and very much like some of the old Mackie analog boards, much like there's a blanket covering your speakers. In that case there are no "magic" EQ settings I could give you that will help. "Zeroing" an EQ is not a term I've heard, so once again I'll have to assume, and in this case I'll assume that your "zeroing" is the equivalent of a flat or bypassed EQ. However, and as I've already said, there's no concept of "flat" until the system has been properly tuned and processed.
The Heil mics have a very neutral sound through most boards. They have their own quirks and nuances, and like any other mic they're not for everyone and everything. Too each his own, good luck in your quest.