First of all if you give two yes answers to any of these four questions:
Two "yes" responses indicate that the possibility of alcoholism should be investigated further. The questionnaire asks the following questions:
1. Have you ever felt you needed to Cut down on your drinking?
2. Have people Annoyed you by criticizing your drinking?
3. Have you ever felt Guilty about drinking?
4. Have you ever felt you needed a drink first thing in the morning (Eye-opener) to steady your nerves or to get rid of a hangover?
Then DO NOT USE ALCOHOL IN ANY FORM and do visit your physician and share your answers with them. Further evaluation is then warranted.
The original discussion I isolated from the OP are as follows: "There will be pressure to not take breaks even in rehearsal, because, unfortunately, there are only 9 musicians total in the pit orchestra... I'm prepared to play whenever I can in rehearsal and lay off on anything not important...I may also ask the other player take over lead at times. Any advice on surviving this?"
I detect anxiety in these responses. Does alcohol help? Uncertain but in some reviews it may:
Alcohol in orchestras: musicians speak out | Culture | guardian.co.uk
Alcohol & Music
In control studies, there are none. Some positive evidence on beta-blockers but in meta-analysis, not so much (See Cochrane Review). In this review SSRI antidepresents show solid evidence for benefit. Problem: They cannot be taken just on the day of the performance and I cannot warrent long term use of any medication for a short duration performance.
So is alcohol safe to use? It is if the screening questions yield more no than yes answers; AND dosing is minimal. One drink is what I recommend, perhaps a second if the duration of performance is over 4 hours.
Can it work? In theory it can, but there is no conclusive evidence that it will; however,there is likely more a chance that it will calm nerves if this is leading to a performance anxiety than har of leading to retirement or death as long as it is used wisely and responsibly.