I really like #3, Daryl. It's about 1,000 yards shorter than #2 (5,250 vs. 6,250), but I think it's a bit more interesting and has fewer dull holes (the 3rd on #2 is the single worst hole in Gullane); also, #3 probably has less in common with #1 than #2 does, so you can think of it as yielding a rather more different experience. If your group is hung up on length, go for #2, but I think it can be really instructive and interesting to see how some of Scotland's really short courses can be so much fun, so I'd cast my vote for #3. (Plus, #1 + #3 is £10 cheaper than #1 + #2, if that matters to you!)
Cheers,
Darren