How to create new hard - soft values for new units Japan 45?

[Mit Sigel]

My primary sources are from The Combined Arms Research Library collection of WWII operational documents. They are GHQ AFPAC O.I. NO.1, Staff Study Operations Olympic, and Downfall Strategic Plan for Operations in the Japanese Archipelago.

Numerous units are missing from the OOB that comes with the game. Some, like 8" and 240mm units can easily be picked up from other OOB's. Not sure why the designers left them out of 45.

None of the planned chemical mortar battalions are included. I can look at another OOB and see a mortar battalion with a strength of 18 and H/S as x and y. The information I have says the chemical mortars were organized as 3 12 tube companies. Can I just change strength to 12 and unit size to company without worrying about the H/S value?

How about new units I can't crib from some other OOB? Like the rocket units? The USMC was using rocket units that fired a Navy 4.5" which had a heavier warhead, and shorter range than the 4.5" deployed with the 422nd rocket battalion fielded by the Army.

How about the double-barreled 20mm Oerlikons fielded by USMC AA battalions? The Corps' AA battalions were reorganized defense battalions without the artillery. They featured 12 double 20's, 12 40mm's,  12 90mm's, 12 .5o M2 HB, and 12 .50 WC.  Is there any rule of thumb that guides determination of hard/soft values for individual weapons, much less blending them?