I would spend some time going round marking the inventories of the shops to see what you can steal, miss out anything that would give you too much of a problem, and see how it goes. If your climbing is good enough to circumvent the lifts, and you have a good script for safe passage through the sewers, you can steal all 3 tiers and should be fine. At least there is a bin there to let you atone for any slip ups. Even if you have to miss the odd shop for the time being, you should learn well enough, then you can hunt/pop boxes/make friends for an hour before starting again.