We will have the range advantage when the river change like this and we will most likely shove our strong made hands on the turn. So make sense to bet river.
We have to decide if we want to have two sizes or one. With two size strategy we can bet pot with nuts and blocker/bluffs and bet smaller with Qspade and Ks and some bluffs.
If you want to use one size strategy I think going small is the best. We will have tons of value compared to bluffs and thinnish value so small size is the best.If you need to be perfectly balanced, Its most likely easier to achieve that with 1 size strategy. Having some bet/folds and bet/calls.
Vs bad villain I think 2 size strategy make most sense. To get max value when we have flush over flush. bad players are often bad at VB and bluff river and will often checkback to much.
Dont forget to leave some flushes in your checking range so we can call river too