Ok, this worked better than I think any I’ve done since Proserpina, though I think still lower than that one - planet Hethi open now off Norkyna. 
Might open a TNT portal later to it near my other one.
… However, I think this can be improved on. Still had a LOT of open ocean - so lots of emerald, but I’m not aiming for that. This calls for another experiment. 
The general idea of a lot of small land areas to get more shoreline and shallow water does look to be good. 
But I might need more. And Ocean might need to go, I had put that back in for this.
Hmm. Well, if next test works better I’ll post! 