I'm not sure why "DetectOutboundConnectMethod" has been removed. It raises the question is it now set to one of the previously available options or to "none". I remain on software 1.3.0 (Build: 2824) and still have "DetectOutboundConnectMethod", although mine is set to "none". If your software is hard wired for the option "Assume connected after a short delay", then that will add a further short delay compared to the setting "none".
The "S0" setting only has an effect when applied in DigitMaps, not OutBoundCallRoutes. However, if your DigitMap is well crafted, then an exact match with [2-9]xxxxxx will be processed instantly with or without an "S0". If you have rule such as "xx." in the same DigitMap as [2-9]xxxxxx, then an extra two seconds will be added to the processing time unless you add the "S0".
Exact timings may be available via syslog. It's a while since I looked, but it might be interesting.
Timing by ear is very difficult as you are waiting to hear ringing tone from the called party and that may be influenced by all sorts of variables at their end.