Looks like you have excellent ventilation on your hives Robo. Mine are not vented as nicely..
The only argument I have about bottom entrance only is when the supers are on. The field bees LOVE the top entrance. During a flow that small top entrance is often too small. I have seen many times like this where they prefer the top entrance. Once the flow slows, they return to the bottom entrance, but always seem to use the top entrance a little.
I dont normally use a queen excluder, but when I find I have a queen that wants to move up into the supers I will put one on, and have noticed the use of the top entrance greatly increase.
I know he was talking about top entrance ONLY, I am saying have both, and get the hives up off the ground a bit. Top entrance doesnt need to be more than a 1.5 or 2" by 3/8 notch. I am not a fan of drilling holes in my supers, but it is an option if you have no phobia about boring through that nice box.
Michale Palmer advocates a 3/4 inch hole in the nuc's he uses, but I believe it was more of a ventilation thing than an entrance, and Rob's boxes appear to be upper society bee houses with the sweet climate control he has installed.
I have had skunks and toads hanging out in front of my hives. I had hives on single pallets, and have wandered out late in the evening to just watch, and found two or three toads sitting happily in front of my hives zapping any bee that came too close.
I raised them up another pallet and that seemed to fix the toad problem;
Skunks are more determined. Setting Cinder blocks and laying 4x4's across them gets the hives up about ten inches or so. I have not found any scratches on hives raised that high, and as a result of this height, I found that working the hives raised that high was SO MUCH nicer. Less worry about weed eating around them, and my back fell right in love.
My stand across the pond here is too high. It is actually fine until I have two or three supers on top of the hives, then it is just too high.
I keep a live trap near each set of hives. Usually baited with Leftovers.
I have caught the neighbors cat a couple of times, but she seems to have learned to stay out of them now, so usually its possum, coons, and skunks.
The problem comes in for most folks when they find that SKUNK in their live trap.. It is easier to deal with than you think.
Take an old sheet, hold it up, and approach the trap smoothly. Dont be jerky or hasty. Simply drape the sheet over the trap, pick up the trap, set it in the back of the truck and transport. Put the trap on the ground, pull the sheet out from under it and gently roll the trap upside down,and open the door. being upside down the door will stay open, the skunk will wander out and hurry away. I usually let them get a ways away before I give them lead poisoning to insure they never return.
I have never been sprayed doing this, and I catch five or six skunks a year. First couple of times you do it the heart hammers pretty good. Great way to test the ticker and make sure its working well!