Basement intake/exhaust

I want to install some intake and exhaust port holes for some 6" ducting in a basement with no windows. It is a concrete wall that extends about 10" above ground level. Currently there is a 4" exhaust for a drier (which needs to stay in use for the drier).

Is 6" too large of a hole to install? If so can I install multiple smaller holes to allow enough air flow?

How do I go about actually doing it? I have very little home repair and handy man expertise.

How much would it cost to have a contractor come in and install a hole with a vent on the outside so all I have to do is build my grow room and hook my ducting up to the appropriate vents?

If you can get away with a 4", can you not 'T-in' to the drier exhaust? The extraction fan would have to go last in the line though or your clothes would end up smelling of the plants.

It will be 6" ducting with 2,400 watts in cool tubes. I think I will need 6" openings. The basement does have one window which I plan on exhausting out of, but no windows on the opposite side for intake. I thought it might be easier to install a hole on that side rather than try to run 30 feet of ducting from the window to that side. That's way too much ducting, especially if I install ducting outside the window to make sure i'm getting fresh air and not just sucking in the already heated air by having intake and exhaust directly adjacent.

6in is fine in a concrete wall. They also make 6in dryer cover so you can make it look like a reg hole. You will need some equipment if you plan to diy. It is a pain but really doesnt take that long with the right tools. Im betting it would cost you anywhere from $200-500 to hire someone to do it for you or you can rent what you need at HD or where ever and do it your self. Just call and tell them you are ventting your oven through the basement and need to cut a 6in hole. They will set you up with what you need. Also if you have a widow for exhaust then why not use the air in the basement?

I will be using co2 enrichment so I want to pull air from outside to cool the tubes. When it becomes cool enough I will turn off the AC and have a separate fan exhaust air out of the window to bring the temperature down. When it gets even colder than that I am going to hook up the intake/exhaust to the inside walls (instead of the outside walls) and heat the basement with the excess heat, and also run the separate filter/fan combo as needed to bring it down to temp (on a controller).

The set up I have now yields around 16-18 ounces every 5 weeks. I am not looking to expand the set up, but I want to get it set up correctly and if it takes a little bit of money to do it properly so I can maintain a perfect environment then so be it.