almost 6 months... I had this set, CLE + 21mm preasph and it worked well on the CLE at all focusing distances; the focusing patch is never hidden. This 21mm on the CL will not show the focusing patch for shorter distances, for its viewfinder has a shorter base length.
You want anyway to use an external viewfinder with the CLE, therefore having the lens hood visible in the VFF is not a problem. Moreover, a 21mm lens is very appropriate for zone focussing, I would rarely use the focussing patch but prefocus and compose.