Ok, so there are no larger clamps for Sense that I’m aware of but here’s the bigger issue… you don’t know where those wires go. By the picture we can see it’s 4/0 aluminum which is rated for a 600v - 205amp service with just ONE wire/leg. There’s no need to have 2 x each leg for the panel size that you have.
If, for example, you have clamp #1 of the correct leg but clamp #2 is on the incorrect leg to then you will get 1/2 of the usage measurement (assuming there’s no/little load on the wire that goes who-knows-where). Both clamps have to be on the leg to the service side.
Since you don’t know what those two wires go to it’s a complete guessing game and no one here can tell you for sure what you have going on. You need to figure out where those go. The Sense app will read the correct voltage even if you have one or both CTs on the incorrect leg(s), but the usage should be imbalanced.
Another possible scenario is that you have both clamps on the non-service leg (assuming all 4 aren’t service) and you are simply reading the voltage for the dowstream panel, or wherever it goes. Point being that it’s all speculative at this point.
I’m still not comfortable with the double tap issue that you have either. I’m still going to recommend that you contact an electrician and figure out what’s going on. OR, if you have the blueprints from the building we would be able to tell what goes where.
This would be a question that I’m sure @JustinAtSense would have to ask the internal team about, since there’s two scenarios that would most likely work; 1 - It’s configured like a dedicated circuit or 2 - It’s configured like a 400amp panel. Neither is correct in your case if in deed they are in parallel. Again however, because all of this is speculative at this point it’s really mute until we know where those wires go/come from.