They will put in a zero stop on a VX 3. I thought they just started that on the VX 6. isn't it 150 for just the the turret swap.
600 yards you could do for under $200. The Nikon Prostaff that I use works great with Strelok+. You can use the bullet drop, or dial in with the turrets.
Just looked at options at the leupold custom shop. a VX3i 4.5-14x50 with 30 mm tube. change cross hair and add m1 turrets for right around 900. I may go that route