Do I need to trim the dishwasher drain line to prevent water build-up from the disposal? Also are elbows OK here

We replaced the sink recently, which required taking off the disposal and installing it on the new sink, and also re-doing the plumbing since the new sink's drain would be further back than the previous one.

For maybe two days we had everything hooked up except for the dishwasher drain line to the disposal, which required a part that was in an unexpected part of my local HD store…so I finally got it on my third trip there.

Anyway, I installed the Insinkerator drain coupler which is a rubber reducer going from the dishwasher outlet on the disposal, to the DW drain line. Two questions:

(1) My DW drain line is really long. Currently, it goes from a hole near the bottom of the sink cabinet, up to a clamp beneath the counter (high loop), but then there's enough excess for it to go all the way down to the sink cabinet floor, then back up to the disposal. When we temporarily had everything attached except this connection, we discovered that, past some level of water (collecting in the disposal before draining), water could back up out of the disposal and spill out at the DW connection. This makes me fear that water will come out of the disposal and could take up the long "low" loop that goes down to the floor and then back up to the clamp under the sink. Any down sides to this? Should I cut it shorter?

(2) We installed the sink in a corner cabinet, and the cabinet is designed so that instead of going all the way back into the corner, it's cut off, making a 90-45-45 triangle of wasted space. As a result, quarters are close, and the DW drain line connection to the disposal is cramped. Should I install some sort of elbow in between? Right now it's a rubber reducer connected to a rubber DW hose on one side, and the plastic disposal outlet on the other. I don't like clamping rubber to rubber, so maybe a plastic or metal elbow would be good…thoughts?

Thanks in advance!