No moonshadow, that isn't what she wants...
Yes, they do make drilled out tubing. It's 1/4" and drilled with a laser.
Hydrofarm sells it...as do others. Hydro stores will have it or you can order it online, I'm sure. 20 ft and 100 ft roll. bout $12 & 20 respectively on price.
You can use a regular timer for on/off..alternating it with your fan/ventilation system and timing it so the fan comes on (and CO2 goes off) before the temps get too high. There are also a bevy of controllers out therte that will do this automatically in a variety of ways..through timers..or through actuall ppm readings of Co2 in the room.
IMO, it all depends on how many plants you're doing if CO2 is truly woirth the expense. There's about a 1/4 increase in yield if done CORRECTLY and levels are kept at OPTIMUM in a 24/7 mode. (can't be done with yeast or manuallly in any way)
2 plants..10 plants...prolly not worth it (unless it's a TREE GROW)
10-20 and above..it may be worth it..but again..you really need to spend the $$$ on a proper controller to see the true benefit....and if you have a large area..need to invest in a propane or nat gas CO2 generator for the space.
Go to Green Air..CAP...etc and look at their wares. It's all geared to growin.. and you will see what they are doing...etc.
good luck
bt dt