Okay, with 2200 trained soldiers, that translates to 26.5 Battalions, 20 HI Battalions and 6.5 crossbow battalions.
I'd keep 1 HI battalion and the half a crossbow battalion in SD at the Bloodkeep.
Lys gets its HI Battalion garrison.
Leaving us with 24, 19 HI and 5 Xbow.
The Crossbowmen are most effective either from the walls, or with a solid group of infantry in front of them, so keeping that and our sell-swords capabilities in mind...
Northern Slum Landing - Wolf's Teeth (800 Pikemen and 400 skirmishers), and 3 HI battalions
Southern Slum Landing - Long Axes (450 Armored Infantry), and 2 HI battallions and 1 xbow battalion.
Main Harbor Landing - Marco's Marksmen (500 Myrish Crossbow, 1500 spearmen), and 7 HI battalions
Inner City Tower Deployment - 3 HI Battalions, 2 xbow battalions
Anti-Daemon Tower Deployment - 4 HI Battalions, 2 xbow battalions
Edit: It uses 71 tons of our steel to equip them, taken with our 35 tons of steel to the Night's Watch, we have about 44 tons of steel remaining.