If nothing is bound to EFD or SATA, then the PRC should absolutely be 1%. This is regardless of whether your devices are truly thin, or fully preallocated.  Now, the receommedation for preallocation with FAST VP is to NOT do it.  Extents that are preallocated but not yet written to are still candidates to be moved by FAST VP.  As they are not written, they will be considered idle and will be demoted down to the lowest tier in the policy (likely SATA).  When the application finally writes to those extents, the data will be written to the lowest tier and so will get the performance of the lowest tier until they heat up sufficiently for FAST to promote them.  If there are a large amount of writes going to the SATA tier, the write pending level can increase an impact the overall performance of the array.  So you need to be careful when preallocating and make sure that the benefits of preallocating outweigh the possible perfromance impact of having those allocated but unwritten extents demoted to the lowest tier.
I'm new to FAST so this question might be dumb.  The question is will fast/vp fill up say an EFD pool if there is not enough capacity in the pool but the demand might warrant it being in the EFD pool.  I obviously want to avoid any host write errors.  We have SATA,FC,EFD thin pools on vmax 5876 and the majority of the volumes are not preallocated and applied a 100/100/100 fast policy.  All devices are bound to the FC pool.  
Will FAST/VP fill up a thin pool?