Personally i cannot see the problem with most of the kit being used . it is an aid to accuracy . as long as it does not touch the floor and within the rules , plus being wihin a time limit . go for it . it is really the constraints of weight and time that will keep it straight i reckon .
to keep it as simple as poss , i would say for sitters & kneelers , that your time of two mins will start from the moment you bum/knee touches the bean bag ( now let's see anybody with a complicated syetem , get ready to shoot and shoot two targets in two mins ) for standers , time would start as soon as his foot touches the shooting line . any blithering about when it is the competitors time to shoot will result in a docked target after a verbal warning from the line marshal .
the only support allowed on standers would be the sling , single or double point .
Now lets see somebody get around those rules . time and weight will kill the people who want to buy an advantage i reckon ??? HOLLY