Lee, you've seeking GT angling nirvana if you want a casting line without the wind knots!
They are unfortunately part and parcel of fishing with braid. If you choose a really smooth line like Varivas GT or Varivas GT SMP or YGK Ultra Castman, then you are going to get more wind knots, not less. You can of course reduce the incidences quite significantly. The first is not to overfill your spool, the second is to look at your casting technique, the third is the weight of the leader you use and the fourth is your connection.
As Mike as written, don't overfill your spool. This is one of the primary causes of wind knots. This is why I tend to question it on the forum here when people make extravagant claims about how much line they can get onto a spool. Packing the line on really tight will help you get a fraction more line on but not 20% more! If you are getting that much on, then you're overpacking your spool. The manufacturers do know what they are talking about when they recommend spool capacities.
Casting is a whole topic on its own so I am not going to go into it here but good technique reduces the incidences significantly. If you use heavy leaders like say 200lb or upwards particularly with PE6 or PE8 Varivas GT, then you will get more wind knots for the simple reason that the heavier leader takes that fraction longer to get through the guides and meanwhile, it has a huge quantity of braid flying around behind the stripper guide. If you want a heavier leader, I'd suggest you think about using a bite leader segment.
On your connection, having your connection between braid and mainline where it is already off the spool makes a big difference. The compromise of course is you end up with a shorter leader. I also find that slimline connections to a single strand leader seem to have less issues than a twisted leader.
