Hello,
I'm not really sure that there were standardized timings for pulse formats, I have many systems that have different delays in them.
I can tell you that the duration for the ACK/HANDSHAKE tone is slightly different between receivers, my Radionics D6500 defaults to a 1.2 second tone, my ITI CS4000 is about 2 seconds, and my Radionics D6000 is about 2.8 seconds. I haven't ever had a panel really have trouble with tones that are around 1 second, though I'd suggest going slightly longer than this, as the really old panels will need it to detect the tone reliably.
A good reference for the digit timing and such is the Radionics D6500 program entry guide, as it has defaults for how long the receiver waits for the next round of digits, and how long it looks for the next digit. The receiver defaults to waiting up to 6 seconds for the next round of digits from the panel, indicating that it won't take longer than this for panels to send the next round of digits. The receiver also waits up to 1.4 seconds for the next digit in a round by default. Effectively, the panel shouldn't have more than 1.4 seconds in between digits, and shouldn't take longer than 6 seconds to send the second round. Additionally, the panel should wait longer than 1.4 seconds before sending the next round of digits, so that the receiver doesn't count it as part of the first round. There doesn't seem to be an industry standard for a minimum for these values, so it is not easy to give suggestions on what you should use, but those maximums are good things to keep in mind. If you'd like, l could take some measurements of what the various systems reporting to my receivers are using, perhaps it could be useful to you to have recordings of multiple different panels reporting?
In terms of the time between the panel dialing and the receiver answering, it really depends on how long it takes for the call to be routed to the receiver, and for the receiver to detect and answer the ringing call. Most panels will wait about 30 seconds for this process, but some have an option to extend it to 45. I have never seen it actually take that long for the receiver to answer, but you also have to consider that most receivers will provide multiple different handshake tones for different formats, and sometimes the 1400hz or 2300hz one isn't early in the list. I'd say 30 seconds is a reasonable amount of time to wait before making another dialing attempt.
I'm not sure if you're trying to make a dialer or receiver, but if its the receiver, you should also remember to wait about 2 seconds after answering the line before sending the handshake tone, this lets the line stabilize and is a standard feature of most receivers. Another thing to consider if making a receiver, is to support the pulse formats other than 4+2. There are also 3+1, 3+1 with checksum, 3+1 extended, 3+1 extended with checksum, 4+1, 4+1 extended, 3+2, the list goes on and on.
Hopefully I can be some help to you, as I know that finding information on the really old formats is quite hard. I'm personally trying to find information on the Radionics BFSK format.
Keith