Touring - Saddle to bar height ratio

I've only owned mountain bikes and hybrids. In both cases, I found the most comfortable height for the handle bars to be about the same height at the saddle. I've just bought a used touring bike and I've adjusted the saddle to the correct height for my legs, but I find the handle bar too low. It's barely okay when I'm gripping on the top part of the bar, but when I grip the bottom, I can't see over my helmet. Is there a correct ratio?
When I look at my hybrid, I see the seat is about the same height as the handle bars. I'm comfortable with that.
Should I have my LBS raise the bars and change the cables accordingly?

Yes, that would be a good idea considering your stem, if traditional, has a long quill to allow that. If your stem is threadless, it's a bit more involved than simply raising. Raising your stem also shortens your saddle to bar distance somewhat so you should be aware of that as well.

There's quite a bit written on the Rivendell web site about the advantages of higher handlebars - they advocate handlebars about even with the saddle for optimal comfort.

http://www.rivbike.com/

Tourists use the drops very rarely, just for big headwinds and steep descents.
Touring style drops are often shallower than racing drops. Yours may be too deep.

There is an objective physiological limit to how much lower your handlebars should be in relation to your saddle assuming you have set the saddle at the correct height. If your thighs touch your torso at any point in the pedal stroke when your hands are on the drops and your ebows are slightly bent(relaxed), your bars are too low. After that, how you set your bars is a matter of personal preference.

There are conflicting studies that say a more upright position allows better breathing and that a lower position creates more aerodynamic efficiency. In the absence of wind tunnel studies and VO2 max testing, you have to find what best suits you by trial and error. But your thighs should not touch your torso.

I had an arrangement that felt really comfortable, but I ended up getting headaches because the bars had been too low.

The lower the bars, the further back you'll need to bend your neck. This supposedly stretches the strap muscles that run across the top of your head. I doubt it happens to many people, but the 'exercise headaches' I got were caused by these muscles inflaming. It took a while to diagnose!

The headaches aren't dangerous or anything, just annoying.

--Biggs

Thanks for all the great advice. I took the bike to my shop and they put on an extension and changed the cables. It is much more comfortable now.