Electronic Alarms and Home Security Devices - Adding 2 wire smokes to VISTA-ADT

I want to add three 2-wire smoke detectors (model System Sensor 2WT-B) to my VISTA-ADT panel which, I believe, is very similar to a VISTA-20. I understand I need to use Zone 1. My questions are:

1) The wiring diagram that came with the detectors show two connected. Can I add all three 2-wire smoke detectors to zone 1?

2) according to a VISTA-20 manual, "The alarm current provided by zone 1 will support only one smoke detector in an alarmed state". I am keeping my non-security connected smoke alarms in place. Is this a recommended configuration, i.e. only having the ability of one smoke in an alarmed state?

3) My panel has 600ma for aux power. In one place, the VISTA-20 manual states 2a for siren and another place it states for a UL installation, total panel power not to exceed 700ma. My current aux power (before adding the smokes) is 200ma and my total power is 350ma (I have a 150ma 90db piezo sounder). Each smoke alarm is 130ma in alarmed state and 100ua standby. Do the smoke detectors add to the aux power calculation even though they do not connect to the aux power terminals? How do I calculate the effective current draw? All 3 for standby and only 1 for alarmed state?

I am assuming that this is a Safewatch 2000 which is the equivalent of a Vista 20se (what does the diagram on the system enclosure door say...?)

Yes, you can put more than two smokes on the loop; the diagram is an example. The specs for the system on page 7 of the installer manual tells us you can have up to 16 2-wire smokes on zone 1.

Two wire smokes don't count against your Aux power limit because they are current limited (it's already calculated into the system power consumption). Only one can actively be in alarm at a time, but thats all you need. The zone will not be any more in alarm with more detector heads tripped (Remember, it uses the system siren output; the individual detector heads don't have individual sounders).

These are smoke _detectors_ not smoke _alarms_, an important distinction.

The system is a Safewatch 2000. I have been reading a a Vista-20 manual. I will look for a Vista-20se manual.

I am keeping my 110VAC smoke alarms in place and will be adding the smoke detectors for additional protection.

Thanks MrRonFL for the information! Now all I need to do is install my cables.