For how the plants are looking which is decently healthy if your ec on your run off is what you say 0.2 lower consider bumping it up slightly so if your feeding at 0.7ec now try 0.8 to maybe 0.9 then monitor.
Typically i try to aim for level or a 0.1 ec drop though all that depends on whats being consumed and gets complex after that if you go down the rabbit hole.
as for levels to feed at you likely have latent nutrients in your mix and also every nutrient is different as far as EC goes so ignore what other may run at and monitor your plants more so and adjust accordingly cause example i may feed at 1.78ec but im also in coco and different nutes vs say a soil or soilless mix grower that may have nutrients in their media and is using something completely different.
Keep at it they’re looking good.
Edit… adjusted my post to match your values