Tracked Security - BTCUSD in this example but can be changed anything.
Index - Current Security / Tracked Security
Inverse Index - (1 / Index)
(Current Security = ETHUSD in this example)
Works across all periods and Securities.
Can format lines and colours, but won't be appropriate to plot all three lines at once.
Easily see currency pair without cluttering up your chart or requiring another chart (especially for members with free subscriptions).
Can be BTC vs SNP ...if you wanted, something which you couldn't find in the standard list.
I have experimented with several combinations, but if there are any issues, let me know.