When you say the gauges are too small or too big, do you mean the samples you have knitted aren't fitting the pattern gauge? If that is the case, adjusting your knitting tension, or needle size to fit the tension of your knitting may be the key.
As Jan said, you can't go wrong with anything you knit. If it turns out to be too small for the first baby, maybe it will fit the next. If it's too big, believe me, they will grow into it. And so will the next one. Good Luck... on all your projects.