all good questions.
1. Application. Yup, dumping grapes through a hopper into the crusher de-stemmer or press. That de-stemmer sit's on top of a bin and winds up about 4 and a half feet off the ground. However at some point I plan on sizing that up, so I'm trying to accomodate for future height. Sitting low the height is about 5 feet, up to 8.5 if needed.
2. Yeah I'm making this stand alone to keep use of the fork-lift.
3. It will not be bolted to the ground, but the overall working surface is asphalt, so I'm not concerned about it sinking in.
4. Tipping is definately a factor I'm worried about. Not sure how long to make those feet, or if perhaps adjusting the pivot of the dump ighter so it doesnt hang so far out. though I feel like that complicates the build somewhat.
5. The grabbers to hold the bin would be 1"x1" - 1/8" ish thick bar stock, should be plenty strong for that.