I have now produced audio files of four multiple movement works using Finale and GPO. I found that Finale's mixer seems inadequate when the score has many MIDI tracks. The Finale User Manual suggests a number of things to improve this situation one of which is to "Save and Join Multiple Audio Files" in a DAW type program. This strikes me as a poor solution. Once the MIDI is converted to audio you can no longer tweak any MIDI settings and cannot take advantage of the better MIDI handling that is likely available in the DAW program.
In most cases would it be better to export as a MIDI file with all tracks still available and little or no added effects (such as reverb) and then polish the MIDI aspects of the piece before mixing and mastering the audio. In the case of "God Rest Ye Merry Gentlemen" on the Christmas CD I would try to tighten up the violins at the beginning, add proper volume overlays to the horns, spread the various string and choir sections over appropriate parts of the virtual stage, and then try to mix and master the final product.
From listening to the GPO demos, items available on some members websites, the Christmas CD, and pieces available in the Listening Room, it is clear to me that some of you have developed excellent procedures for getting from a completely notated score to a polished recording.
Norman J. Nelson