32 gauge (smaller wire) will make it easier to get lower ohms. 28ga is larger wire and will need to be longer than 32ga. It's not exactly accurate because some wire is broken off after installation and you have to account for that.
I'm not sure if you just worded it wrong, but what you have written is wrong. Thicker wire (the lower the gauge number) always has less resistance for a given length than thinner. Kidney puncher actually has a handy chart of the approximate resistance per foot of all their gauges of kanthal.
I would say its much simpler to just record what gauge of kanthal you used, how many wraps, and what size object you wrapped on. Measuring the resistance of each strand before wrapping is redundant and fiddly. And like you said, its a ballpark figure anyway because of the wire lost on leads.
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