Wyrm Armet is better for breaths, but for those who don't have the armet, this is as close as it gets.
I just did some actual numbers with healing breaths...
75DRG/37WHM
Healing Breaths
Base: 216
AF Pants: 233
Deep Breathing: 409
Deep Breathing + AF Pants: 446
Saurian Helm: 316
Saurian Helm w/ AF Pants: 344
Deep Breathing + Saurian Helm: 510
Deep Breathing + Saurian Helm w/ AF Pants: 557
Look over those numbers and you'll see the gains from Saurian Helm...
Without AF pants equipped, Saurian Helm will give a 100hp gain.
With AF pants equipped, Saurian Helm gives a gain of 111hp.
Deep Breathing does not boost the effect.
Keep in mind that Deep Breathing is triggered before the healing breath kicks in. By equipping the Saurian Helm you are adding 100~111hp to the final result.
There are obviously other factors that can increase healing breaths such as wyvern exp bonus, wyvern hp+ gear, AF+1 pants, etc. With that in mind, there are later variables, but these are the basics.
[Edit]
Looking over what somebody posted on wiki, trying to figure out where people are getting these numbers for the % gain this helm gives, I noticed a trend. Saurian helm's gain is based on the gear you are using. For example, note that above with AF pants, the gain goes from 100 to 110... a 10% gain. The data found on wiki with AF+1 pants shows the gain goes from 100 to 115, or a 15% gain from the base gain from the helm. With other things in mind such as wyvern exp bonus gains which caps at 30%, the gain goes from 100 to 130, a 30% gain. Add AF+1 pants and 1000 exp to the wyvern, and you gain 45% or 145hp. Keep in mind that SE's math also works in tenths, explaining the above mentioned 111hp, but I'm using 110 since it's the actual base value.
solid evidence concludes...
[] Saurian Helm adds 100hp to healing breath
[] Wyvern HP+ gear and other stats that affect the wyvern stack seperately with the Saurian helm, giving a bigger boost to the initial gain from the helm.
Example:
Say Healing Breath base gives 200hp, and that with AF pants (HP+ 10%) you got 220hp. Now if you unequip the pants and use Saurian Helm, you get 300hp. Equip the AF pants again and you will now gain 330.
200hp from base
20hp from AF pants gain
100hp from saurian helm's base
10hp from AF pants gain
------------
330hp
[/edit]
Took me a while to test each breath, and work out all the other gains, notice the trends, etc, but there you have it! ENJOY!
*** 3.8.2008 *** UPDATE
Got my wyrm armet today (very happy, very excited!), and ran the math as I did with the Saurian Helm...
Wyrm Armet: 332
Wyrm Armet w/ AF Pants: 361
Deep Breathing + Wyrm Armet: 525
Deep Breathing + Wyrm Armet w/ AF Pants: 574
Base gain: 116hp
Additional % bonus from wyvern HP equipment is added the exact same way as it does with the Saurian Helm.
Just throught I'd throw this in to finalize the original post! ENJOY! :)
Edited, Mar 8th 2009 10:16pm by Zapix