I run a 550 gallon skimmerless system using a large clam to clean the water. I absolutely love this design. So I would get a beautiful Derasa or Squamosa and go skimmerless. The LPS and Softies will love the extra nutrients not having a skimmer will provide. There will be a lot of people who disagree but from my 25+ years of experience the most bullet proof reefs I have ever owned have been skimmerless. Good luck! Nice setup!
100% would get a slimmer but you could wait a month or two. On a set up like that I would get some quantity with a NYOS skimmer quantum 120 super quiet https://amzn.to/2SW2OBb. I run it on my Red Sea reefer 350 series and love it!