I have a 5" Indo, it hangs inside the same stump with a 5" Syno.. They get along fine. Their other tank mates are a 5" Bulls eye Bush fish, 2-2" butterkoferi, 8" Lima Shovel nose, and a 3" Pleco.
I have 12 tigers. Biggest 12 inch. I have kept syno petricola for five years always in the same tank. I can honesty say the tigers never show any interest. Must be those nasty spines! They all swim harmoneously together.
Total I have 7 petricola. Range from 3 to 4 inch.
Yeah they will be perfect together I have many large dats with a 8'' syno and they live perfect together. The syno is a bit territorial over his spot in the tank and the dats dont mess with him...lol