The Reverb_D module uses what is often called a Feedback Delay Network (FDN) structure. In this structure the delays aren't left and right, but they're all in parallel with a large feedback matrix which controls how they're fed back. If you're interested in a good introduction to FDNs you can check out Julius O Smith's page on the topic (https://ccrma.stanford.edu/~jos/pasp/FDN_Reverberation.html)
So the delays aren't really left and right, and because of the matrix the order does matter. You can obviously sort the delays that way, and the reverb will probably sound similar, but different.
A full reverb would usually be built by adding a multitap delay module, like multitap or easytaps to simulate early reflections, followed by some diffusors, like the diffusor module, then a Reverb_D, then maybe some EQs for the output. Setting the delays lengths and feedback values tends to be a dark art, and honestly my approach is usually just to fiddle with it until it sounds good.