Hello,
Thought may be of interest? Put this in after a few weeks of gathering all the pieces.
Dirty Harry back box speaker panel swapped with Virtua Pin back box speaker panel, Pinball Pro 5.25" speakers.
So both speakers are equal size with equal sized openings.
Complete version
https://virtuapin.net/index.php?main_page=product_info&cPath=17&products_id=117
DIY version
https://virtuapin.net/index.php?main_page=product_info&cPath=17&products_id=114
New BB spkr panel has 5.25" equal sized holes for both speakers.
5.25" WPC Pinball Pro Speaker kit, includes cabinet subwoofer with cross over (Yellow? Black +. Black -.).
2 5.25" bb spkrs.
Back Box mounted balance knob for bb/cabinet spkrs includes wiring to bb spkrs.
http://pinballpro.net/shop/williams-wpc-complete-speaker-kit-swtr-hf/
On Dirty Harry always has a Credit Dot for Time and Date not set. Pinball Life NVRAM from Lock When Lit.
https://www.pinballlife.com/index.php?p=product&id=3666
For pictures posted in "The Dirty Harry Club" page 17,post# 837.
https://pinside.com/pinball/forum/topic/the-dirty-harry-club/page/17#post-4381487
Did same for TAF a while back. TAF also got pinsound and stereo wiring harness so closer to Stereo. Same can be done to Dirty Harry.