Cowl air questions

I'm working on a cowl air set up using a cylindrical air box from a 1994 Range Rover.

A couple questions - and for reference, this is just set in place in the picture. It is not mounted - just resting on a block of wood, not at the correct height, or positioned left to right properly. Also, I am going to turn it around so the lid is attached to the cowl hose versus the throttle body hose.

• the vacuum tube that you see in the picture with the blue tape on it, that used to run to the stock airbox, can I pull it off and replace it with a small filter, or does it need to be run to the new airbox. To that end, if I need to run it to the new airbox, should it be before or after the filter?
• The hole in the top of the airbox, should I plan on sealing that up? I can't really figure out the purpose of it.
• I'm going to need to do a 180* arc out of the front of the airbox and back towards the cowl. Will that restrict the airflow or cause any concern? I know that the preference is to do straight runs whenever possible.

Reconnect the hose after the filter the engine draws vapors through it and reburns them.
I'd plug the hole or it kinda defeats the purpose of the cowl intake.
Specter cowl intakes have some sharp bends and seem to work.