I used to add a second EUR expression because the first scalp was working. Overlap liquidity feels forgiving until both positions lean the same way into a US data ripple. The cut rule is mechanical: shared budget across EURUSD and the EUR crosses I actually touch in that window.
Overlap specifics
- Max combined open risk in R, not "two small ones are fine"
- No adding correlation after the first fill without flattening something else
- If DXY is driving, treat USD legs as the same story
What correlated-risk rule survives contact with your London–NY EURUSD book?
I also watch whether GBPUSD or gold is carrying the same USD story. Overlap days can load the book with one macro idea across three symbols. The cut rule is really an honesty rule about how many names one thesis gets.
When the cut rule triggers, I reduce the secondary name first and keep the cleaner invalidation if I keep anything at all.