I don't think "mainlining" means what you're thinking. But either way, a recirculating or oscillating fan is always good to give your plants a little breeze. I just hope I'm understanding your question correctly...
I stand corrected, my apologies. I hadn't heard of the Main-Lining growing technique before. Where I come from, "mainlining" refers to intravenous drug use. I'm not going to be any help on this one, but thats a crazy looking plant. Good luck with your grow!
I mainlined my peppermit kush (pure indica strain), and it responded very well!
I mainlined at 3rd node (cotyledons not include) when the plant had 5 nodes, to let it create a good root mass.
Remember to remove everyting but the growing tips u wanna use. Everything is better if whole the structure is even!!
The fan is necessary for air circulation, and if u have an extractor too, it's the best!
Using the mainlining you should not have so much problems with mold because the plant only grows a limited numbers of colas and leaves; there is a lot of space for the air to flow.
If you use the mainlining, remember that it is not only lst. Removing many parts of the plant, slows down its growth.
And always remember that you want a fan that is exhausting air 'out' of he room rather than having a fan blowing into the room. As MrWhat said, this it a good idea to remove heat and/or replenish fresh carbon dioxide to the plant. peace