Changes in the intended opening message can be done in two ways:
1) By editing the message 1 of the proposed topic (as you have done).
or
2) By submitting a new message in the same proposed topic.
Either way, the individual message can be used as the new message 1 of the promoted version of the topic. Method 2 has the advantage that it preserves message 1 in its original form, and thus the nature of the changes can be easily tracked. Even a third or more message can be written, as to be the proposed message 1 of the new topic.
Also, by using method 2, the topic is automaticly given a "bump" on the topic list, bringing the changes to the attention of the various admins. If method 1 is used, the changes may well not be noticed by the admins.
I am currently giving my careful consideration to the present form of message 1. While we could nit-pick on it for a long time, I am inclined to think it is now "good enough". But I don't want to rush my decision.
I may take the liberty of doing a few tweeks of message 1 myself. If so, I will try to remember to save an untweeked version as a new message in this topic.
Stand by - The topic will probably be promoted within the next hour, quite possibly early in the next hour.
Adminnemooseus