Are we ever sure? I'm not one to advise you, since I have no experience with a tank that size.
I will say that with a macro algae tank, a higher bio load is helpful in maintaining the higher nutrient levels the macros need. In reef tanks, we struggle to keep nutrients low. With macros, we struggle to keep nutrients high enough to maintain growth. It's a different mindset that a lot of macro keepers have a difficult time adjusting to.
But you have just started the tank. Right now, you have a tank full of macros, with almost nothing in there to feed them. Lots of instability, as bacteria and algae get established. I tried to keep nutrients low when my tank was new. I still got a nasty algae phase, and my macros got smaller and smaller, until they disappeared. When I added fish, the macros came back.
In the end, you're going to run your tank as you see fit, and Mother Nature will do her part. You'll make adjustments, depending on your priorities, and eventually you'll realize your vision.