Ok, after some.. consulting... (My thanks to them on their... insights, much appreciated) culled the list down to:
Generic Mod Enabler - v2.6.0.157
[E:\Games\SteamLibrary\steamapps\common\SH-megamods\SH4-megamods\FotRS-U-EN v1.7\MODS]
001- 100_FotRS-U v1.7
001B- Nihon Kaigun v1.1
001C- Nippon Maru v1.6a
001D- N.MaruV1.6a-N.KaigunV1.1-combinedroster
EAX_SoundSim_FOTRSU_1.7
FI-OQ-FOTRSUv1.7-EN(patched)
New Sounds Interior-Officer Quarters mod
Enhanced Sounds for SH4
450_MoonlightzSonarLines
901_Strategic_Map_Symbols
Realistic Floor Tiles for Fleetboat_Interior-Officers_Quarter
Smaller seaplants-small
Sober's Better Sand v2
Sober's better rocks v2
Sober's 3D waves mod
802_TMO_torp_tex_FotRSU
Splash_effect_DC_bombs_bullets_shells_1.0_for_FOTR SU
806_PeriscopeSplash
Improved gun tracers - torp damage mod
302_MoreDifficultAI001
650_LotsaDudz
FOTRS-U v1.7(only) Sub skins in 4k
Of special note: Save folder, was nuclear cleansed... upon activating the above mix... before rolling with a test run of the mix.... just, to be clear, on that point, thanks. 
Booted up... then ran a nav map test run, using that as a test bed run, with the peri splash... as before, not understanding why, but.. for Me, it is working fine. am... baffled as to what is not working for others... as I nuke sanitized the game saves folder... up to the point of it not existing, until I ran this test of the current mix.
From what I observed... wake & such, is as reported before... just like when you're charging all out flank speed ahead, just... at a.... hmm 1/4 the effects level of the "All ahead flank" effects, from the sub body as it barrels full bore ahead.
Same end results... from what I can see of, the peri mod patch, released just a day or so ago... is working, as it did (the original peri wake splash mod, that is... here in regard to v1.46 & the preview, v1.6X) when it was done up for v1.46 & with the preview release v1.6X...
Same, as far as I can tell for the torp tex mod 802_TMO_torp_tex_FotRSU...
End report.
M. M.