need feedback on clutch vs flex fan and shroud

Unrelated but underdriving the waterpump is never a good idea.
I always recommend to direct drive your 7-blade fan until you get your cooling system sorted out, and are confident in it's ability to do the job.If you don't already have one, your pump should be wearing an anti-cavitation plate, and the stat should be an hi-flow type.After that you can start experimenting.
When you get to clutches, the Thermostatic is the way to go.