How separate was parade armor from tournament armor? I know some garnitures had pieces that were interchangeable for tournament and field use.
Most parade armour was used entirely for show. Tournament armours, in particular, were made with thicker plate and had interchangeable components as you mentioned. I've never seen a parade harness with any kind of crazy embossing or repousse work that was doubled for field or tournament use. Men who could afford these harnesses were wealthy enough to own armours for each specific role, and would not worry about a single harness having enough interchangeable pieces to use for multiple affairs after spending so lavishly on them!
Some garnitures were equipped for both field and tournament use, yes, but this is understandable because the qualities of a tournament harness are not that different from what was required for field use. Lighten the cuirass by removing the additional plates, switch out the gauntlets for lighter (often fingered) ones and remove any face or shoulder reinforcements, et voila.
This, however, is beyond what would could expect of parade armour. The amount of detailed etching, repousse and embossing that went into most of these harnesses typically made the harness a bit more bulky for the amount of protection afforded, and oftentimes impractical components would be added to parade harnesses for extra flair or to capture the spirit of "Alla Romantica," or the Roman era. Rarely have I seen designs for parade armours that include extra components, making them less than a real garniture.
-Gregory
