Hi Paul, You don't say whether you are in the U.k or not but, if you are, where I live in Lancashire there are sweets such as Vocal Zones, whilst Sanderson's Specific is available as a gargle/drink or sweets. Recently I also bought in Upton on Severn, Proctor's Pinelyptus Pastilles as recommended by M.Maurice Chevalier, Mme. Sarah Bernhardt, Miss Ellen Terry, Sir Henry Irving etc. All the above work for me and I can sing with the Shellbacks Chorus for up to an Hour indoors or out quite comfortably, and/or a full evening as part of a 4 part harmony group or joining in other peoples chorus.

I must also confess to having plenty of lubrication especially in a dusty barn usually a long mineral water with a shot of some alchol. Port is also brlliant on its own or diluted.

A good tip is to ask your chemist for something suitable. Good luck with the gig and hope the above is useful