Spin on traditional squirrell fan Carbon scrubber

So I as thinking I really don't want to drop $100 plus on a new fan.

I'm going to be building a new 6'x3'x3x cabinet (all the room I can affort). Given my budget requirement and lack of ability to cut a large circle in the plywood I'll be using. I thought of the following.

4 of those furnace filters made as you typically would make a carbon scrubber and 2 box fans sandwiching the filters in a push/pull fashion. I'll have this entire contraption bolted/screwed all together so it's one piece.

Each 20" lasko box fan pushes 3226 CFM when set to the #3 setting.

I will also have 1 smaller box fan for the intake. Estimated CFM is about 1900CFM.

I have all these at my disposal and I think they'll work well in the push/pull fashion but wanted to get other people's opinions.

Here's the link to the lasko box fan specs.

Lasko CFM Spec

Any input would be great. Good or bad.

Thank you.

bump?