My original water pH is 6.2, and my alkalinity is not very high, at 77.3 (as ppm CaCO3).
My calcium is very low (2.5) and sulfates too (13) so I am trying to bring those both up, but not using anything with more sodium as my sodium is relatively high at 112. I also need to watch my chloride to sulfate ratio as my Chloride is quite high at 127. Magnesium is basically non-existant in my water.
So sounds as if you are on a well and not too far from the JDF (I'm assuming that's where the sodium and chloride are coming from but it could be elsewhere). The low alkalinity and hardness are a blessing. The high sodium and chloride potentially a curse. You might want to give serious consideration to cutting 1:1 or even 2:1 with RO water. The former would approximately halve everything and the latter reduce to about 1/3 i.e. sodium down to 37, chloride at 42, alkalinity at 26 and very low calcium. Sulfate at 4 could also be considered as virtually absent. Unfortunately, there is no other way to get rid of sodium and chloride than dilution with RO or treatment of the whole volume through an RO system which amounts to the same thing.
Now it may turn out that even these levels of sodium and chloride are not problematical for you but I would certainly think that you would want to experiment with lower levels.
According the the E-Z water spreadsheet, if I add 5 grams of Gypsum and 2.5 of epsom salts to the mash, it will bring up my Calcium to 57, and my sulfate to 194, and Magnesium to 11.
The spreadsheets are fine for calculation of mineral additions such as these. It's only when you start adding bicarbonate and carbonate that they fall down somewhat. Magnesium is something you do not really need to worry about as malt contains plenty and magnesium generally isn't considered flavor positive.
The beers I've been making have turned out quite well, but one thing I definitely notice is that the hop aroma does not come through at all. I'm hoping that increasing Ca and SO4 will help with this.
Sulfate will have an effect on perceived hops bitterness but I would look into some other things if aroma is disappointing. First off, of course, is to be sure that you are using a good measure of aroma hops and adding it late in the boil - even at the end of the boil. The essential oils that are responsible for aroma are quite volatile. It doesn't take much heat to drive them out of the beer.
The spreadsheet says my mash pH will be about 5.65, which is at the high end of the acceptable range, but I shouldn't need much acid to lower it, I would think.
Assuming that your base malt is a pale ale malt that's probably a fair estimate of the mash pH. Maris Otter, for example, seems to have a distilled water mash pH of pretty close to 5.6 and you don't have enough alkalinity, especially if you do dilution, to pull that very far. Nonetheless it is likely that a bit of acid will be necessary to get you into the 5.3 - 5.3 region. You could use citric for this but another thought would be sauermalz if you can get some of that. A percent or 2 sauermalz in the grist should have you just about right.
You probably do not need to treat your sparge water. It would be best to verify that with a pH meter but at your alkalinity level you shouldn't go over 6 before having collected as much as you want. With an RO dilution you can be certain you are safe. With out, you are very probably safe.