Reverb distance starts with the return level
Judge ambience by its place in the arrangement, including the spaces between phrases.
Begin with the dry sound
A reverb that sounds lovely soloed can wash over the next phrase in the mix. I set reverb with the whole track playing, never from a soloed tail.
Set the dry source at its intended level. Add the reverb return gradually while the arrangement plays, not from an isolated tail.
Check whether the ambience supports the phrase or distracts from the next entrance.
Compare one dimension
Change one reverb parameter at a time and listen to the same passage. Return level, decay and the timing before the reverb becomes prominent answer different questions.
Shorten the loop only after listening through the complete phrase and its gap. A tiny loop can conceal how tails accumulate.
Review the transitions
Listen where instruments stop and where the arrangement becomes dense. Consider return automation if the ambience needs to change between those moments.
Check the result in mono as well as stereo, and keep a dry comparison available. Prefer a setting that supports the performance across the section.
Rory