Yes, definitely let her eat at all but the pre-shot 2hr window. We want to keep that particular time free of food because we're making the safety decision about shooting, and don't want to be fooled by food influence. But at all other times of the day, just feed her normally-- maybe some of the midday tests will be affected here and there, but it's a good tradeoff in that case.
As for removing kibble as suggested by your vet, we usually say not to make that change "while giving insulin, without testing frequently". This is because of the dramatic effects in some cats I mentioned above. You are testing, and you are going to reduce the dose from what took her down to 41 yesterday, so those are two good safety measures. I would still probably wait until Sunday, when you are able to test all day, to remove the kibble entirely. That will also give you a day or so to see how she reacts to the lower dose.