I bustle wedding gowns as well as Mardi Gras presentation gowns.
A simple bustle for presentation gowns uses a large covered hook and
eye. This is a "one point bustle". The eye is placed at the waist
of the gown (where ever you want the top of the bustle to be) and a
hook on the train at the point that will bring the train up from the
floor that lines up with the hem of the gown.
To decide the placement of the hook I follow the center back seam
down from the waistline. About halfway between the waist seam and the
end of the train pinch the fabric and bring it up to the eye
placement. You then adjust your pinched spot to even out the train
with the hem of the gown. If the train is to high move your pinch up
the seam a little, etc.
It takes a little adjusting to get the train to the correct length
but once you fiddle with it you'll get the hang of it.
On wedding gowns instead of coat hook and eyes you would use covered
buttons with loops. The buttons are on the waist line the loops are
placed on the train. When the loops are brought up to the buttons
the bustle is formed. Then you can adjust the folds in the bustle.
Word of caution... be sure the seam you are bustling to is enforced
or the gown could rip from the weight of the bustle. To bustle a
heavily beaded gown I use an inner belt at the waist of the gown.
There are more complicated ways to bustle from the under side of the
Ides of March Design Group