My friend's proofreading-challenged friend -- me! -- meant to say: "Does anyone HAVE one they could copy or photocopy ...," etc. Sorry for the error, and thanks again for your help.
The instruction manual for the 309 will have drilling instructions, but nobody really does that themselves.
An HW-19 IV with a Jr plinth doesn't make sense. It sounds cobbled together.? Is it a Jr. with a IV platter/bearing upgrade? 19's come with armboards drilled for what you need, SME included.
The IV requires a VPI "Super Armboard" to comp for the added height of the IV platter; this isn't part of the IV platter/bearing upgrade.
If I'm correct in my guesswork, order the Super AB from Elusive Disc, drilled for SME.
Sme's UK site is currently offline, but the US distributor is Sumiko. They can probably get you SME manuals.