@Ngaatu
I still can't say I understand what you are asking but let me explain how covering the short end protects against a correlation breakdown.
The actual correlation between EURUSD and USDCHF is -93%. This means 93% of the times these counters go in exactly different directions at the same speed. It means that 7% of the times this does not happen. But his 7% is what moves the price spectrum of price difference of the dollar in the Euro and Swiss economies.
Now if you take a long on EURUSD and a long on USDCHF at 9.00 a.m. and at the same time take a short of EURUSD and a short on USDCHF. If the market moves in any way along the currency spectrum,your equity remains unmoved - correct?
One of the pairs (say shorts) will hit your profit target (say 30 pips). You will close this pair. When your profitable pair is closed and the price spectrum reverses,you make a gain in equity. If it proceeds in the same direction,you equity gets drawn down but less so because it was exposed much later in the price spectrum than would have been had the shorts not been opened at the begining.
With a reopen procedure for both long and shorts,and with 0.1 lots to every 1,000 dollars,you can survive for eons even WHEN THE CORRELATION OF -93 falls to a lower correlation (what you are calling a "break-down"). This is because your reopened shorts will keep booking profits.
Like I said,the trick is in the re-opening procedure to minimize drawdown and maximize gains. Most math fellows can already guess what this procedure is. Simple calculus.
Have I answered your question?