Recommendations for an Estuary Sounder

[LuckyFil]

I'm looking for recommendations from fellow Raiders for a sounder for my little tinny (12 foot) that I use in Brisbane Water, so its essentially a shallow water area apart from the odd spot like Rip Bridge which has a few massive holes. I mainly target flathead which I'm not expecting to see on the sounder but do want to search for bait schools where the flatties may hang around. That's apart from wanting to know about the bottom features - water depth, holes, drop off's, any structure e.g. rocks, snags etc.

I've been reading up on the Lowrance base model (I think it's a Hook 4) and the Humminbird Helix 5 which is a step above in screen size and has dual beams so is more expensive.

Do any Raiders have experience with either of these or recommendations for others?

Cheers

Fil