Be sure to only raise the TA by 10 ppm. You want to keep it at 70. (You could also just leave it at 60 ppm for now and if and when it drops below bring it back to 70 ppm and not higher! )
You have never said how big you pool is so I cannot help you with dosing info but for everh 1000 gallons a SCANT 1/4 cup of baking soda will be in the ballpark to raise the TA by 10 ppm.
I would put in 3/4 of the amount you need over a period of several days--a small amount each day (because you just did the stain removal and you don't want pH to jump quickly lest the stains return., wait 24 hours after the last addition, adjust pH to 7.6 if it is higher (use your acid demand test if you have one)--If it's lower don't worry too much about it, wait another day your TA.
If it it still too low start adding the remaining 1/4 of the baking soda left over a few days and repeat the pH adjustment and testing.

I would not do this until you have finished with all the stain removal and your chlorine is holding properly.