High seat advice

[Rabid 1,936]

Fellas,

Am looking for some advice or tips, and I've posted it in here as you lot use them more than anyone else.

I am in the process of building a high seat, it will be a permanent fixture so not too bothered about the weight, but I do need to be able to move it to site for erection, i do have a forklift to help.
I need it plenty big enough for two people, and I have the basic idea of,  1m front to back,  2m left to right, 1.5m tall at the back, and 1.8 at the front, with a sloping roof down to the back.
the basic frame will be made from 1inch box as I have a heap of this available.
I would like to be able to shoot from 3 sides, so will be planning a rail at the desired height on those 3 sides, with a foam padding to rest on, or make a 4inch timber shelf (undecided on that one yet) the back I was thinking I would totally board out (it will back onto a very thick hedge so limited view anyway.)
below the rail on the other 3 sides I was thinking to board it out, to help keep wind, noise and smell down, and built with a boarded floor.
What's the best design you have seen, used, or have, to gain entry, I am unsure if I should have a hinged trap door in the floor, or a door in the front or sides, but I think the shooting rail will be too low to make entry anything other than difficult from front or side, so am leaning towards a trap door in the floor.

Its looking likely it will be 3m off the ground.

This will be a multi purpose seat, deer, fox, and general wildlife spotting/photography.
Any and all input appreciated.
cheers,
Rob.

[sussex 5,776]

Something like this , you can have a look when your down ...

[Rabid 1,936]

Similar but I want it a bit more enclosed/sheltered from the elements, with a roof on it, otherwise very much like that mate.