My latest acquisition in this kind of box was the C&F Grand Slam Permit Box (Model: CFGS-3544).
Why this box?
I was looking for a box to carry on me in the surf. Thus it needed to be waterproof and large enough for surf flies (usually size 6-1/0). The C&F Grand Slam Tarpon box was also in the running originally, but when I went looking for it, I found out it was on back order. Of late the club members have also been talking about saltwater flies for the surf at our local fly tying meetings and in general the fly sizes are remain at the smaller end of the aforementioned range. Thus I felt the permit box would do the job well for my purposes.
In Review: C&F Grand Slam Permit Box (Model: CFGS-3544)
Holding Flies: My largest concern was that the flies in the lid would be crushing those on the bottom of the box. I'm happy to say that was not the case with the flies I tested. The largest was tied on a size 1.
I'm sure if you tried, you could make a bulky fly large enough to get crushed in this box, however I have a large fly box for just that kind of fly too.
The only concern I see is with the length of the flies. Most of tails of my flies reach past the the next row of foam. A little pre-planning in fly placement can solve this problem, and most of the flies I used in the photo shoot came out of my large fly box. The next series of ties on the blog will probably be flies tied to fill this box.