Cant get it fully pressed against the back so leaves a small gap, think thatll be an issue? Or should I cut silicone globs on the top to push further back?Go with the peninsula.
How did you position the returns? I feel it kinda takes some space in the center and leaves the returns a bit close to the front of the tankI did mine in the center, I have the 29g as well. But for my location the peninsula style would have been harder to maintain. The globs of extra silicone in the top corners can certainly be trimmed, I trimmed my corners, but just be careful with your razor blade because it's an awkward angle you need to get in to get those upper corners.