Well, ideally, you would need to calculate the EURIBOR leg yield as a weighted average of a number of ER contracts (7 at the moment). However, the 4th and/or 5th contract should serve OK as a proxy.Quote from chintanthakkar:
The current yield of the 4th/5th Euribor contract is 2.002 whereas for the Schatz Dec09 it is approx 1.785.
Do you think looking at the absolute difference between the two yield could help decide anything about the direction of the duration neutral trade?