普通に考えれば、大きいほど良い。
https://www.activair.cz/data/katalog/files/507.pdf
The On-Board IS system ensures full use of system-level helium resources for any operational condition. A patented control system continuously regulates the helium allocation per pump, thereby increasing the pump-to-compressor ratio for reduced cost of ownership. In addition, On-Board IS cryopump systems reduce power and cooling water consumption.
