While the larger flutes can certainly make use of the FluteGels and Cushions for prevent slippage, their primary hand and posture issues derive from the weight of the instruments themselves. This is where the Bass Boost or the Support Stand come in (both of which, despite the name, can be easily used with both alto and bass).
The Bass Boost is an elegant piece of machining that sits on the floor with an adjustable tripod base. The player simple rests the tube of the low flute's footjoint on the padded cradle on the top, transferring most of that weight to the stand.
The Boost has an enormous range of heights - from 2 feet to 6 feet - and is also lightweight and easily transported in a carrying case that comes with it.
The Support Stand is a smaller piece of equipment that's designed to work for the sitting low flutist. The base rests on the player's leg or chair and the padded top cradles the middle of the flute, transferring that weight away from the arms. The tradeoff for the small size is that the Stand does only work for the sitting player.