Syntactical Rules:
1). The names of instruments should always appear in English.
2). The names of instruments need not be capitalized.
3). Instruments must be spelled completely, with no abbreviations.
4). Instruments must be separated by commas, and never with slashes.
5). Never use an & symbol.
General Guidelines:
6). The original instrumentation must be provided, rather than an arrangers instrumentation.
7). The orchestration must be provded, rather than simply stating "orchestra".
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9). Instrumental Ordering:
Orchestral: woodwinds, brass, percussion, harp/piano, strings (with score order within those groupings).
Solo instruments: Vocal/choral pieces: voices first, then instruments in score order or orchestra as above.
Exception: In a woodwind quintet, the horn is not the bass instrument, so bassoon should be listed last.
10). The cello part that follows the bass line of the keyboard part is a continuo part, and should not be listed as something separate to the continuo.
11). Instruments that are either offstage or optional should be listed last. Thus: "(+ ad lib.: 2 clarinets (B♭), tuba)", or "(+ offstage: 2 trumpets (C), trombone, tuba").
12). For a large orchestra, instruments can be provided on different lines according to family.
Specific Rules
13). Must use "English horn", and never Cor Anglais. Must use "Horn" and not French Horn. Must use "piano", and not piano forte, and "cello", never violincello.
14). The names of the oboe d'amore and the viola d'amore should always include the apostrophes, and take the plural forms oboes d'amore, violas d'amore.
15). The term "voices" should reserved only for solo vocalists, and never be applied to orchestral parts.
16). Choruses should always be described as mixed, male, female or children's when appropriate, with their composition shown in brackets using the standard abbreviation (e.g. "mixed chorus (SATB)", "mixed chorus (SSATTBB)", "male chorus (TTBB)", "female chorus (SSA)", unless they're in unison ("children's chorus")).
What thinks everyone? If there are any suggestions, feel free to include them in the actual draft (and don't feel limited to just the instrumentation field, you may edit anything in the manual, of course).