Reason for Lapua brass for 32 S&W Long HBWC?

The Lapua 32 S&W Long brass I have has an ID of .312" while my Starline brass measures .310".  Is this the reason PardiniUSA recommends using Lapua?  Also, since my Dillon SW powder funnel has an ID of .312" is it really necessary to use it?  Why can't the S funnel be used instead where it won't grab the case as much?

Yes but not just the id you can measure, it's the internal profile, it's tapered on starline and other +p design brass. You can measure max seating depth prior to base crush with drill shanks or gauge pins. 

RP is also a very good choice if you can find it.  I still can't fathom what barrel mfgrs were thinking when they knew what factory ammo dimensions were...oh well good enough for these saps?

Bad choices of twist, groove diameter and chamber design

I recently bought some Lapua brass, it is like night and day to reload compared to Starline. Definitely the goto 32 S&W Long. Big price difference, though...big.

Fiocchi are the next worst...but not too bad