Hi,
Some input from the more experienced members please.
I need to re-house 3 T's all of them arboreal.
I have already decided on a size of 220x220x400h.
What I need help on is the 'type' of enclosure if I can call it that.
There are 3 types I know off:
1. With lid on top and ventilation in lid
2. Fixed top and door in front for front access, side and/or top ventilation
3. Complete enclosure fits over a base allowing very little substrate, almost like nr. 1 but upside down version of it.

Which one of these designs is the better option?

I think nr 2. for access to the T's when they are bigger and more scary (to me) but the hinges are a bit of a problem for me.

What ventilation, cross / top ?
Thx.

From my little experience I'd say:
No 3 is exclusive for things like Avics, where every time you open the top lid you destroy the web tube.
Arboreal spiders tend to run upwards for escaping, which makes the top lid fun, but also useful. I use the bag method to rehouse or remove them for major maintenance, so for me up is good.
I like cross ventilation with a vent low down and one higher up on the opposite side or on top. Different gasses have different mass, so to my little wet mind it seems ideal to have a situation where there is a place for the heavier gasses to escape.
Good luck!