Reloading .303 British : Advice for a newbie?

Bear, if you can spring the $24, buy a Lee Collet Neck Sizer (they are sold individually).  You'll be very happy with this die. 

 

I use a F/L die when necessary.  But even backed off to size the neck it still requires lube, the collet die does not and it minimizes cold working of the neck (a collet die squeezes the neck to the final diameter as apposed to a FL die that squeezes the neck smaller, then expands it to the final diameter as you withdraw the case).  You can get different size mandrels too direct from Lee Precision if you want to play with neck tension.   

 

I believe the collet die is one reason I've been able to get so many reloads of my brass, perhaps as many as 50.