The Airobic 151 will be perfect. On 100 yards of slope, small jibs and butters are what you have to work with and the Airobic does those thing perfectly. The ET 154 would be an awesome board for you, but it would be overkill if this will mostly be used indoors and the extra flex of the Airobic will be big fun in that setting.
That's great, I wanted to go as short as I could but wasn't sure I'd get away with the 151. The specs on the new ET sound awesome for sure now that it has the faster base but I can only justify one new board, maybe next year. Thanks again, top advice.