I'd say, given the site itself is long enough, that the difference between can do & can't do is the skill of the driver & the directions given by the spotter. There has not been a 30' max CG that we have not been able to get our just <36' selves into.
There have been differences of opinion between driver & spotter but the driver has final word. There have been a few, very few, times when the driver has had to concede defeat & move to another site, however most times when the spotter has doubts, she gets told yes we can now get us in there. Any unsolicited advice from surrounding inhabitants is politely ignored.