I can only from my recent experience. After agonizing and researching I landed on Fluval Stratum for a new 20 Gallon planted aquarium. I wanted a full carpet.
I was worried about ammonia spikes in a new tank and algae outbreaks. I was also wanting to well establish the plants.
This is what I did:
Dark Start the Fluval Stratum in a lidded 5 gallon bucket with a sponge filter for 6 weeks. Dosed starter bacteria during this period.
Dry Start setup with the Fluval Stratum substrate and plants. This was for 3 months.
Flooded tank and monitored closely. I had 1 minor green algae bloom, I think I over fertilized. Amano shrimp and snails, with a bit of manual cleaning took care of it.
Things seem to have stabilized but I am watching closely. Fingers Crossed.
CO2, Fluval 207, Seachem Matrix, Seachem Purigen, Hygger 957
Not sure my carefully considered research and planning worked, or if I just lucked out.