Hoot, I do resize my .284 brass after fire forming them, With a .284 FL sizer.
Here's the process I use
I cut down and trim .284 win brass to 1.703
Debure the inside of the case lightly and deburr the outside as normal
I use a LEE carbide 45ACP flare die to open the mouth of the case up just enough to be able to set a bullet on top of the case with out trying to balance it.
I then prime the cases
Next I charge the case's, after dropping a charge I set a bullet on top of the charged case to unsure I don't double charge and make a mess.
After all cases (50 at a time) are flared, primmed, charged and a bullet resting on top of them I put my LEE carbide 45acp bullet seating die in the press with the die ran all the way up while still having enough threads in the press to properly hold the die, And the bullet seater ran almost all the way down and seat the bullets to my OAL
After seating all the bullets to my OAL I lube them lightly, Install the .284 FL size die with the De-Capping pin removed and give them a pass through the 284 FL sizer to get rid of any bulge in the Unfired .284 brass.
I wipe them down with a clean rag and their ready to be fired, And yes they work very well!
For loading the fire formed brass, I don't need to flair the case mouth, deburr, or ream them at all, The last fifty I loaded I did run them through the FL sizer again but little to no contact was made, I DO put a side crimp on them and they work great.
I used the 225FTX for the first firing and the 250XTP for the second firing.