Elevator top Idle sprocket

On our 2 stage cascade elevator we are preparing to drive the first stage. The plan is to have two chains (one on each side on a common drive shaft at the base and Idle Sprockets at the top. We have looked at a few options at the base as for sprockets and figure bigger would be better for chain wrap and speed. For the Top Sprocket is there any reason since its simply an idle pulley that a 16T sprocket can be placed up there.

What other information would help here to make some educated decisions.
Stage One is counterbalanced with 2 16lbs constant force springs
#25H chain is currently planed for use.
Redline Motor with 16:1 up to 60:1 Sport 57 Gearbox. (16:1 equals about 2v holding a 20lb stall using 16T, 30:1 equals about 2v holding stall using 32T) *Also concidering if the gearbox is to big then it will have the power to break the chain vs stalling the motor

Our (2767) setup last year was very similar to what you’re describing, including the spring counterbalanced first stage, but with a single #25 chain driving it instead of 2. I don’t recall the gear ratios, but I believe the drive sprocket was 32T. We used a single 16T bearing-mounted idler sprocket up top last year and it was fine. The second stage was compound rigged and driven by 2.5mm UHMWPE cord. The keys to making this scheme work fast is proper tension and alignment. You need to be able to get and keep the chain tension up in order to be able to accellerate hard without skipping chain. If the alignment is off, tension needs to be even higher. If you don’t have rigidity for the idler pulley up top or support for the drive down low, the chain will also tend to skip due to slack in the (obviously) non-tensioned side.