It sounds reasonable to me.

My test kit doesn't measure FC over 5 ppm but I have a CYA kit which gives me a good idea of stabilizer values. I've never had to actually shock my water but if I did, I'd trust the poolcalculator for amounts to add given the CYA values.

Test 3 times daily (if you have the opportunity) and keep adjusting FC with bleach additions. If you can see algae debris drop to the bottom after brushing, then vacuum. If you have plenty of water, vacuum to waste. If you don't, use skimmer socks so the solids are caught in there rather than in your filter medium.

Once your water is clear for 24 hrs, backwash the filter.

That's how I would approach it, anyway.

Anna