In the seconds setting for the snipe, default is set to 6 using the FireFox add-on, what are your observed results for setting a lower time, for example 3 seconds? Will it still get recorded? Is it best to leave at 6? Any thoughts?

You can set any time. Even 1 second.
The problem is when internet connection lags, eBay is too busy or some other network-related reason then you have more chances to lose.

On another hands, it makes no sense to put something like 3 seconds or 1 seconds. If you got outbid, that means that someone put a higher bid, not because someone watched you and bid in the last 3 seconds.
You just need to bid higher or find another item (Group bidding comes handy in this case).

I experimented with different time and got no problems bidding 1 second, but in practice it does not give you any significant advantages compares to 5-6 seconds.

That's all my own experience, of course

Thank you. Could you explain "group buy" and how you have used this.

Thanks.

Groups is a special feature which can help you to control how many items you want to buy.

Please check those two links for basic information about Groups and how to use it:
http://www.myibay.com/login/faq/2/#q10
http://www.myibay.com/login/faq/2/#q11

and some requirements:
http://www.myibay.com/login/faq/2/#q12