CO2 Needle Valve Questions

I need some advice for a CO2 Needle valve to help regulate the flow of CO2 once I go Pressurized. I have looked at the one sold on DrsFostersmith and found the price to be steep. about 37.00 before shipping. I was wondering if anyone had any ideas either for a DIY or some pre made needle valve that is less than what was listed above. Basically I am looking to find one that will allow control down to 1-2 bubbles a second. I already have my regulator and solenoid, but now need the needle valve. I have tried a basic plumbing needle valve, but even the smallest is threaded to large to keep the flow at 1-2 bubble/sec. Any help would be great. Thanks!

Sean