Hi there, I think, the best thing is to stay open minded, as you obviously are.
I had 2 of my children on gas and air only (and first ds was back to back when I delivered him) and I really didn't find it all that bad with them...well, there was pain, but with both of them I coped well without painrelief (or in ds 1's case a tens machine and before that a night in the bath, lol), comparing those 2 labours, my 2. labour was actually less painful then the first, but neither were that bad, like I said....indeed, when I was pg with es I started having really bad pain at around 18 weeks of pg, and well, I honestly thought I was in labour, it was soooo painful. I wasn't in labour though, it was just stretching of the Uterus and ligaments...and stuff....well, a fair few friends felt it was wise to tell me, that if I found something liek that so utterly painful, then there was a chance in hell I would have a natural Birth (nice...)...but I was happy to let them know afterwards, that to me the pain I experienced at teh earlier stage had felt far worse and more painful (although emotional issues were probably at play...I mean, when you start having really bad pain at that stage, and after having lost the previous pg....well, one would freak out, which doesn't exactly help dealing with pain.)!
With ds 2 I had a friend with me, for most of the labour, and she was really surprised by how little I seemed to be affected by the pain, and how calm I was....but with him it was a lovely, if rather slow progressing labour (which was possibly why it was gentler and less painful, I suppose).
With ys, well, I laboured at home and got to 10 cm's (I was planning a Homebirth with him) , that time I was in incredible pain, but still coped on gas and air and positioning myself and what not...but he was my most painful one out of the 3....well, until I stopped contracting for a while altogether...ended up in Hospital with Emergency C-section...but that was due to his position, etc...appaerently....I do believe the painfulness was due to his positioning, that is for sure...
But a calm, comfortable environment in general really does help when coping wiht pain!
I really like Sheila Kitzinger books....rediscovering Birth was a very interesting read, but I know she has got more good books, and there are other good ones, that are about birthing and natural births...