Thats a hell of a list, 43 songs!!
I mean my covers band's list is about the same, 50 or so, but we pick and choose per gig, and usually end up with 9-12 per set!
Can you not request that you learn some of these for this gig and learn the rest of the next gig?
I'm with you though, playing a dep gig tomorrow night, first gig on 5 strings for maybe 4 years lol, so am currently learning all the awful cheese that my band wouldn't be seen dead doing lol. Playing on 5 because whenever i've dep'ed for this band before, they always have random singers that want the songs in all kinds of keys. I figure its easier to re-acquaint myself with (my friends) 5er over a couple of days, rather than having to transpose with a 4 on the fly.
Good luck though mate
Si