hi,
your trigger should back the horse if its back price now is equal or lower than the matched lay price, at 30 seconds to the offtime.
You need to clarify how much the price has to drop below the matched layprice.
The condition is Selections back_price is equal or less than bm_layp
In the attached example I have put the drop at 5 ticks. If you put it too close you might get bounced in and then out again, but thats up to you to decide. The r_ticks calculates the current price ticks.
I have not tested this at all, so test it before you use it.
Good luck
Larp