So, I could have written your post myself 5 yrs. ago. In 2014, I started with a used 75 gallon tank, no sump. I had a Marineland Penguin something or other HOB filter and lots of live rock. It was a hugely successful mixed reef tank and I still have many of the corals that I started with back then.
In 2017, I decided I wanted to keep SPS corals, specifically acropora. So I had a custom sump built and got a CPR overflow box with aqualifter pump. I did have 2 minor floods when the aqualifter failed. But I have hardwood floors which are always in need of a good mopping, so no harm was done. Still successful reef tank, but was getting gnarly. Too overstocked with corals. Never overstocked the fish, still have my original 6.
So in 2019, I decided to go as big as I could reasonably maintain since my husband has no interest in my hobby. I got a Red Sea Reefer XL 425 which is 112 gallons total system volume. I love it and couldn't be happier with my decision.
The moral to this story is, I think you should go for the Waterbox 130 if you can comfortably afford it. I wish I would have just gotten the Red Sea tank back in 2014. So much money on upgrades and equipment that I don't need now.
Just my experience...good luck!