My understanding of saddle-fitting is that you can't really be between sizes - if your sitbone measurement is wider than what will fit on a 143 saddle, then you really need to be on a 155 saddle. So the girly-bits pain that you're having may be b/c the narrower saddles don't support your sit bones properly, leaving all your weight on the soft tissue. This is also why you're not having sit bones pain on the narrower saddles - your sit bones are not really ON the saddle! You should try a saddle in the 155 measurement with a bit more padding and see how that pans out. I ride a Specialized Ariel (it's a mountain saddle but looks great on my road bike). It's definitely got more padding than the Lithia and comes in 155. That might be a good option for you to try.
I need to clarify--my apologies. I measure about 135. According to Specialized system, that puts me between a 145 and a 155, depending on my riding position (more time in the hoods and upright, I should be on a 155, more time at a 45 degree angle or less, the 143 is better). I got sit bone pain on the Jett 143, but I was told by my bike shop that they stopped carrying it because too many complained it was too firm, so that may be the reason there...
I tried a Fizik Vitesse in the bike shop yesterday and WHOH--I finally found a seat that was comfy on my tush! Problem was that the Vitesse does not have a cutout, and apparently from the pain I experienced up front on the trainer (RIGHT AWAY), I need a cutout. Its a Tri seat, and was a little long for my purposes anyway, but it made me very interested in Fizik seats.
Anyway, I'm presently trying the Terry Falcon X (Terry has a great 30 day love it or return it guarantee). It measures about a 152, and when I switched from the Vitesse to the Falcon, my girly bits thanked me. It feels a little stiff near the hind end--it might be too wide, but we'll see how I do on the road. I just don't like the way it looks on my bike.
Thanks so much to you all--all your advice is fantastic! I'll keep you posted on my trials. Keep your ideas coming! I could use all the help I can get!
And, thanks for the tip on the Ariel!
Well, you can't see the saddle when your butt is on it!
Function over form, I say!
Karen
You probably tried this model, right?
http://www.ebikestop.com/fizik_vites...ail-SA1826.php
It is a tri saddle... But Fizik makes a non-tri version of the Vitesse, and the nose shape is very different. I haven't seen the tri version, but I would guess that the nose is squishier than the regular version too. The Vitesse hp is quite firm. I think it's probably shorter as well (it's certainly not a long saddle).
Here's the regular version:
http://www.glorycycles.com/fivihpsabl.html
Not to sell you on the Vitesse, it may be completely the wrong saddle for you, but if you liked the rear of the tri saddle, it might be worth trying the regular version -- you may find that the firmer, lower-profile nose is more comfortable.
Good luck!
Finally got the Fizik Vitesse LIFE and I've done three 30-40 mile rides so far and it is really nice. By far the most comfortable I've tried yet. It doesn't have a cut out, true, and I thought I would really notice that but it is engineered with soft memory foam OVER a cut out so it actually softens as you ride it kind of forming to your shape. The sit bone area is really comfortable. I think this is as good as I can get for now. Thanks to those who sent advice. I've also found some fantastic headlamps== expensive but super well designed and unbelievably strong for their size and weight--- made by DiNotte Lighting who are really nice to deal with. Kind of essential item as the light disappears so early now in New England. Definitely buys some time without that mad lung burning race with the sunset!