Read on and we'll go through all of them. A manifold system is simply a machine that is used to perform a task. There are many different types that can adequately accomplish this. Unfortunately, I believe, there have been several manufactures that have gone to end users and gotten their systems specified as the only adequate option. It would then be tested for it's performance qualities and awarded a second set of points.
All electrodes specify a starting and finishing current required for successful emitter conversion.
The only way to set or adjust your choke properly is by using this gauge. A temperature gauge lets you know when you have reached that point. This is to say that paper is not sufficient to tell when the glass has been brought up to the required temperature. It is possible to use a butyl oil U-gauge to monitor the pressure in the tube. It works just fine, but unfortunately too many people won't take the extra time - even though it can save them untold time to replace stained tubing and virtually eliminates sucking tubes in while bombarding.