Palmer has a spreadsheet on his site; I think it is section 15.3, that explains additions very well and does all the math for you. If you want to do water chemistry it's a great tool.
Mg is needed by yeast, and should be around 15. Calcium is critical, so I'd invest in a test to verify everything.
www.wardlab.com is $17.
The chloride:sulfate ratio leans heavily to malty, which is OK. Some epsom salts would boost the Mg, and add some sulfate, balancing the C:S ratio for you.
But I'd recommend you plug all this into the spreadsheet and start to play with it. Have fun.