I wouldn't lend any of my bikes to anyone, they are set up for me and wouldn't suit anyone else.
You sound a similar size to me, my fixed has horizontal top tube and is a 54, my geared bike is a compact size 53 and is one size to big, I recon a 52 would be perfect, unfortunately I had a choice of 50 or 53 and the 50 would have been too small.