Sorry to hear about your bad experience at The Butte... I have had several weird to bad experiences there myself...
I have soloed at The Butte via shunt (80's!), Soloist, and SP... I much prefer the SP as a chest harness is not required. I know plenty of folks like the modified GRIGRI I just have not personally used that method. The dual Traxion method looks sound but then again - chest harness is needed...
You will, and are, getting lots of opinions on the solo top-rope business here. Perhaps best in a stand alone thread but most folks here have good working advice.
As The Butte is so short and you would likely be there only in drier conditions many of the aforementioned techniques should work fine.
As for the local ruffians... K A R M A !