If you thinking of running a 25' vacuum hose, go with a 25' solution hose. If you have a 50-footer lying around, use it. You're not losing as much pressure with a distance compared to a vacuum loss, where CFM and lift are going to be lacking, because dual 2-stage motors are barely enough. If you had dual 3-stage motors, I'd recommend upgrading to a 2" vacuum hose, you'd get slightly better results even with a reducer since Ninja doesn't have a 2" vacuum port We can debate CFM vs Lift ratio based on hose diameter forever, but if you want to start, do what's best for you. If you have plenty of vacuum hoses, cut a custom length, let's say 15', this should give you a better suction.
P.S. I use a 2" vac hose on
Edic Endeavour( 30') with good results ( twice a year

)