If your roster is stocked with a lot of middle blockers, you might want to consider using the triangle middle formation, which puts 3 middles on the court instead of the standard 2.
As Oregon State assistant coach Emily Hiza explains here, this formation has one MB – the M1 or the "ultimate middle" – who plays next to the setter and is always in the standard middle blocking position. The other 2 middles – the M2 and the M3 – should be players who are capable of swinging on some high balls at the pins and who have solid enough ball control that they can help out in passing situations or play a little defense in the back row.
This video shows a sample lineup sheet that indicates where the 3 middles might play in each of the 6 rotations.
