You won't improve on the OTW system for speed unless you switch to centrifugal pumps, or fit a bigger pump (not available commercially) and you'll need to use a different approach too, as they only pump one way.
Peristaltic pumps are always slow and bulky compared with other types of pump. Why do people use them in some ballast system then you might ask? Well they're self sealing, needing no pinch off valve, bi-directional and they're easy to rebuild.
The shurflo pump can pump about a gallon a minute. Good luck finding a geared pump that will match that, and is small enough to fit in a Vanguard.
You could parallel ina couple of geared pumps, but then you have a current hog of a ballast system, and it will still barely match the shurflo pump volume wise.