SR has 31 cells per "brick" [Tesla's term]. There are 24 bricks per module and 4 modules but those modules are just for packaging and don't have much significance from a cell electrical configuration perspective. The 96 bricks are in series with 31 cells in parallel for SR/+ and 46 cells in parallel for LR.
Each cell puts out about just under 5Ah. Jack Richard
measured one at 4.458Ah. The Tesla
EPA submissions had LR pack totals of 222.81, 221.81, and 225.56Ah; an MR pack total of 181.8Ah and SR pack total of 155.6Ah. Dividing those by 46, 37 and 31 respectively yields: 4.84, 4.82, 4.90, 4.91, 5.02Ah per cell. Obviously those are all higher than Jack Richard's result but that testing was presumably done under more controlled conditions. Assuming 4.9Ah is probably reasonable.
The highest C-rate occurs when pack voltage is low and amperage highest. The SR pack is known to charge at
105kW from low SoC. 360V is a reasonable charger voltage when low. That's 292A [105000/360] or 9.4A per cell or
1.9C [9.4/4.9] at low SoC. The amperage and c-rate decreases as the pack is charged.
If we ratio the LR 250kW charge rate down for the SR, the SR may charge at
168kW. To do that, the charger voltage is probably 380V at low SoC. That's 443A total or 14.3A/cell or
2.9C. This has not been seen publicly, just speculated.
The LR pack has been shown to charge at 250kW. Again assuming a 380V charger voltage at low SoC, that yields 658A or 14.3A/cell or 2.9C.