Salts CaSO4 6.0g, CaCl 1.2g, MgSO4 2.4g plus a quarter tab campden. 1/2 Whirlfloc tab and 2g yeast nutrient at 10 min.
Based on boiling 7.00 gallonsliters at 1.450 for 30 minutes, this will decrease your wort by 0.50 gallonsliters, bringing your after boil OG to 1.482. You wanted an OG of 1.053. It looks like it will be over.