If you decide to try those glass bottles, don't use the needle valve. It is only barely possible to get too much CO2 for that size aquarium, so you would be best to just leave the CO2 line open, running as high a bubble count as you can get. I suspect you will run into BBA problems with DIY CO2 because of the difficulty in keeping the CO2 level the same every day. DIY CO2 typically doesn't give a constant bubble rate, but a slowly decreasing bubble rate followed by a more rapidly decreasing bubble rate. It may be interesting for you to try this, but very soon you will decide you just have to go with pressurized CO2.