Unity 400 Hybrid Pool setup Suggestion ?!?

Hello all,
I'm new to Unity management. we had a old VNX 5300 configured with multiple LUNs and now with our Unity we can create pool and vmware profile.

I plan to go with VVols blocks.

Ok here is my question. We have an Hybrid setup. and we don't plan to expend storage capability for the next 1-2 years.

I'm not sure what is the best to setup and I want to make the best decision at the beginning.

So here is my setup:
104 TB raw in performance tiers
15 TB raw in extreme tiers flash sas

and we have 4 400GB configured as fast cache (800GB).

we are running mainly DEV stuff and about 20% of storage is PROD (internet services, DB and web services)

I have 3 idea of setting up storage.

1) setup 2 pool. 1 pool is performance + fast cache and 1 pool is extreme + fast cache
2) setup 3 pool, 1 pool is about 50% storage performance, 1 pools is 50% performance + fast cache and 1 pool is extreme + fast cache

3) mix all storage in 1 pool + fast cache and let the systeme decide what go in flash or SAS

I would like to use Vmware profile to be able to switch from perf to extreme or from different tiers for specific needs
and I want to be able to use the maximum storage capability of the SAN without loosing storage by a bad config. (like we have right now with LUNs)

For information we currently (old SAN) have a storage capacity of 65TB and we are almost full, so the new Unity offer a little bite more and having VVols block will help us to no wast space.

And a bonus question is 4+1 better then 8+1 raid 5 ?

Any suggestion or comment will help me the do the right choice for our need.
thanks you

Martin