One thing I was surprised to learn about nuclear costs is that there's a fixed component that is basically the same regardless of technology (SMR vs 'LMR'): the civil works.
There's a certain amount of concrete and such that needs to always be built, and if you go with a "cheaper" SMR, then the fixed cost becomes a large portion of the total project budget.
So unless there's a specific local need for ≤300MW, it might be better to go with a 600/900(+) MW design if you can tie into a large grid where all of those 'extra' MWs can be soaked up.
There's a certain amount of concrete and such that needs to always be built, and if you go with a "cheaper" SMR, then the fixed cost becomes a large portion of the total project budget.
So unless there's a specific local need for ≤300MW, it might be better to go with a 600/900(+) MW design if you can tie into a large grid where all of those 'extra' MWs can be soaked up.