Most of the steel posts we are using don't have the cross pieces on them. We do have some with the cross piece on them, but so far we haven't noticed any problems with the roots growing into or around them. We also try to keep our fencing to about a 3 to 3-1/2' diameter which keeps it away from the seedling pretty good.

I planted my truckload of oaks yesterday and today. Camera caught some action shots.

There are a few deer around. Should they all be tubed?

only if you want them to grow into a tree.

I have switched to putting welded wire fencing around my trees.
I have pulled the tubes that had trees growing in them for about 4-5 years and haven't amounted to anything yet and replaced the tubes with the wire.
I have planted trees in openings in the woods after a tornado went thru and opened up spots.
Seems to me that when not in full light the tube might be restricting sunlight too much. That plus the leaves that hang on thru the winter that then don't fall down and end up being a block in the tube.
These are White Oak seedlings.

I ended up giving a bunch of used tubes to a guy that was has planted hundred of trees in the Ripon/Green lake area. He also commented on the very low suitability of hardwood trees due to deer..
Claims he planted white cedar and have some that are 25 years old and only 3-4 ft high. The deer heavily prune them every year.

I like the idea of some sort of mesh or screen material D.

I don’t need all of them to grow into a tree. Frankly if half survive, I planted way too many. How many per acre do I need to survive to meet the minimum qualifications? I really wish I could do an oak savanna in my MFL plan, but I think they want them thicker than that!

Perhaps worst case maybe just try some bud capping if you have success problems

I think you'll have a good enough survival rate to satisfy you. It sounds like you planted extra, knowing some won't make it, which is smart.

So my experience in tree planting some 200 white oak, 25 red oak, 25 scarlet oak, and 25 persimmon on the side of a hill where we couldn't use a tractor for planting was we rented a post hole drill/auger with a 2" bit, bought several bags of top soil, and several 20' sections of fiberglass rebar and I cut those down to 4' sections(wear gloves handling the fiberglass rebar, and expect to go through several blades on your sawzall). Then we drilled holes every 25 feet, put the seedlings in, topped them off with the bagged top soil, and used the natural rocky/clay soil on top. I made a post driver using a 10" piece of black pipe with a cap on one end, and we put a 3' white tree protector over the seedling and then zip tied that to the post we drove in.
The one thing nobody mentioned was looking down the tubes checking on your seedlings, be careful as wasp's luv to build nests inside the tubes, and if the you look in quickly, look out for the guards as they will get ya!!!