Usually, you can pull the chain down tightly in the sprocket for at least half a turn. Then look closely at the leading and trailing sprocket spikes. The chain should be completely down between the sheaths and evenly spaced on the spikes. If the chain fit is perfect, you may be able to slip the seated chain loop back and forth a bit on the chain wheel. If the chain is not perfect, it will be easy to notice whether you need more or less links per foot.
Willie X