Advice on Combat SU vs Fortifications

[con]

Looking to see how best to optimize Combat SU when trying to crack fortress cities (looking at you Leningrad).

Based on the rule 23.6.1 HQs will only commit a max of 6 SU to a battle (this is in addition to whatever SUs are attached directly to the combat units).

This makes for a max of 15 if you have 3 CU in a hex (3 SU per CU = 9 + 6 from HQ).
Based on the arty rules Heavy Arty can reduce Fortifications but Engineers/Pioneers are better for fort reduction.

Assume that all the hexes are optimized for HQ position and all CU are in the correct Orgs.

What combination or advice would you give attacking a major city fort hex in a turn.
1. Deliberate Attack 1x with everything maxed out from multiple hexes (eg all CUs have max number of eng support and any other SU you can scrape together) with 6 Max Heavy Arty SU from 1 HQ
2. Multiple smaller deliberate attacks maxed out with Eng SU to reduce forts with heavy Arty with a corresponding drop off in Arty due to ammo expenditure (23.8.3)
3.Only Engineers? Save the Arty for a follow up the next week?

Thanks

[loudscott]

I'll be curious to see how this rattles out as well. Fort reduction was one of my issues with WitE1. I'm hoping the modeling in WitE2 is more realistic.