You don't necessarily need the maximum db reduction for hunting purposes. I can't find the link right now, but the levels for damage are a certain number of minutes for a certain db level, with the exposure time before damage getting less and less as noise level goes up, and past 130-140db the damage is instant and permanent. You may not notice the damage, but it happens and is cumulative.
So the 29db muffs come in especially handy if you want to spend more time in a loud environment than you could with 20db muffs, or if you've got a sound that's 160db+. That means regular calibers at the range for lots of shooting, or maybe a braked magnum in the field for a shot or two.
Extrapolating from that, for hunting, this is what I do: Because the length of exposure to the noise is so extremely limited while hunting, get the noise level below the instant damage threshold and you're fine, whatever you use. IIRC the instant damage threshold is 130ish db+. Standard calibers are 140ish, magnums 150ish, and braked magnums are just f'ing loud.
I used some of the aforementioned Howard Leight electronic muffs this year, and they worked great. Well, except for when they decided to receive the local radio station. I'd imagine that for standard calibers out of regular barrels, even 10db attenuators would be a huge improvement over nothing.
And I just say no to muzzle breaks. I like my ears more than my shoulder.
The numbers above likely aren't 100% accurate, as from what I recall, 20db muffs are plenty for pretty much anything for a shot or two. Treat them as a relative scale and go practice your google-fu.