If you can use the 8 inch filter it will be best,a 6 inch will suffice!
A phresh filer is a brand name of a carbon filter manufacturer
One carbon filter and one fan is all you need for exhaust!
Inlet can be filtered to keep bugs out....I will be using a car filter...cheap! Hepa filters are expensive!
Another reason I suggest a tent is that wall covering cost me $117.00 and tape cost $40.00 for two rolls......the tent costs about the same and a lot less work and no tack and nail holes in the walls!
When weight is an issue go for a filter that is thinner...some filters are two inches thick of carbon and actually flow less than the one inch thick versions.
If you go with the 38 lb 8 inch filter you can still use two lights and hoods....go with a high flow 6 inch fan and filter if you will feel more secure about it.
The tent makers know what their doing when they recommend a filter size which is usually a 6 inch filter in a midsized 4 x 8 x 7 room!