Hi Rory,

I think it doe not work like that (although I don’t know the liter instruments (on IG I suppose);

The value for one contract will be 1/10th all right but the price remains the same (about-ish). Calculated instruments will work on the price, and this is not what you want.
(and if the Mini is not there, you can’t trade it anyway)

If you mean something else, let us know.
Peter

So here you have the Micro (MES) vs the Mini (ES). The Mini is the largest possible (this is IBKR). Personally I see no reason not to use the Micro to see where the Mini is heading. They are not 100% the same, but they are sufficiently the same to see where either is going.
Would my position on the Micro not be 12 but 10, then the gain would be the same when having a position of 1 on the Mini. This is apart from the Commission, which is not included in the gain anyway.

Please keep in mind that this is not CFDs but normal Futures. So the Mini should be a factor of 10 on the Micro.

I hope this helps ?

PS: In the 2nd attachment shows what you literally asked for (as it seems 🙂 ). But as you can see, this leads to something not really wanted.

image_2024-09-26_015028457.png image_2024-09-26_020330028.png