Standard Separating Busk
Heavy Separating Busk
TipKeep in mind that a busk can always be made stiffer by slipping stiff bones into the casing along with the busk (this is usually called an underbusk). Also it can be more comfortable to only stiffen one side of a busk (usually the stud side), keeping the other side more flexible to make it easier to open and close. This might make the corset lopsided, though, so beware.
I'll be using a standard busk in my Truly Victorian and a spoon busk in my Silverado. For the straight-front corset I'll be using an underbusk to keep things straight and help with the silhouette.