Water profiles

I'm just updating my water profile in Beersmith2 and have a few questions, if anyone has any answers they would be appreciated.  I've only ever used tap water for brewing, never tried to alter it in anyway but now I am looking at going the whole hog to see what difference it makes, if any.

I have spoken to a couple of chemists and a couple of people from Watercare and got all the water data I can from my area, Beach Haven, Northshore of Auckland.  My main water source is from Ardmore with occasional top ups from Waikato.  These two water profiles are quite different which has given me a bit of a quandry...

Data is from

http://www.watercare.co.nz/SiteCollectionDocuments/AllPDFs/Publicat...

Ardmore:-

Calcium 7.46 ppm

Magnesium 1.5

Sodium 8.9

Sulfate 8.69

Chloride 13.15

Bicarbonate ?  

Waikato:-

Calcium 19.08 ppm

Magnesium 2.82

Sodium 19

Sulfate 25

Chloride 21.36

Bicarbonate ?  

I can't find bicarbonate levels but it may be under another title...  Any ideas?  Is this important?

I see it is mentioned quite a bit regards some of the Trappist breweries in Belgium.

Unfortunately I don't know what the mix ratio is of the two waters and no clarity was given on this.  I was going to add the two together and divide it which seems reasonable but might be better with a higher ratio of the Ardmore...

What have other people done?