I think 1000 delivery systems is the mininum.
Now for how many warheads ....
Let leave the numbers, because it's meaningless to talk about actual numbers now.
Let's talk about how doctrine and policy would affect numbers. This is what I believe:
1. I believe that if China stick with minimal armament doctrine and non-first-use policy, her warhead and delivery vehicle number will be the minimal numbers that can guarantee an effective, sound and reliable Second-strike/retaliatory-Strike Capability against any enemy nuclear forces.
2. And if China is to abandon minimal armament doctrine and non-first-use policy, She will have to adopt a different kind of doctrine. Well, please spell out what kind of doctrine will it be?
To me, answering the question of doctrine and usage policy will only determine what the rough ranges of the number of warhead would be:
either in several hundreds to 1000-ish, (this is for current minimal armament doctrine and non-first-use policy);
or in more than tens of thousands (this is for a cold war nuclear arms race type of doctrine and policy).
So if you guys think that China should stick with the current doctrine and policy, then the question will be why do you think 1000-ish will better suit China's current doctrine and policy than what China has right now? Is it because the USA (or other potential adversary) has some kind of technological breakthrough that would greatly reduce or even neutralize the effectiveness, soundness and reliability of China's Second-strike/retaliatory-strike capabilities? Well, if you have an answer, show me what that is.
Given that China has made huge strides forward with its ballistic missile and delivery vehicle's capabilities, what kind of answers should I expect from you guys?