Way back when I started this blog, I began by talking about yarnovers. And although I explained then how to do a correct YO for any of the four possible combinations of leading and following stitches, there's an aspect that I left out, so I thought I'd come back and cover it.
In most cases, all YOs are done so that the resulting loop sits in Western orientation, with its right leg in front of the needle. There is a circumstance, however, in which this is not wholly desirable. That circumstance is when a pattern contains pairs of YOs that are intended to be symmetrical, but one YO is preceded by a purl and followed by a knit, while the other is preceded by a knit and followed by a purl. (For purposes of this discussion, I am lumping decreases worked with the yarn in back in with knits, and those worked with yarn in front in with purls.)
In the case of the k-YO-p combination, the knit stitch ends with the yarn in back of the work. It's then taken under the needle to prepare for the YO, over the right needle to form the YO, and under the needle a second time to prepare for the following purl. Of all the YO combinations, this one uses the most yarn, as the yarn makes about 1-1/4 circuits of the needle.
In the case of the p-YO-k combination, by contrast, the purl stitch ends with the yarn already in front, so it's simply taken over the top of the right needle to form the YO, and then it's already in the proper position to form the following knit. This is the shortest of the YO combinations, with the yarn making only about 3/4ths of a circuit of the needle.
The difficulty is apparent: the k-YO-p combination puts quite a bit more yarn into its YO than the p-YO-k combination does, with the result that the hole it forms is perceptibly larger.
The potential solutions are twofold: make the big hole smaller, or make the small hole bigger. In either case, this is done by wrapping one of the YOs in the opposite direction, so that the resulting stitch uses the same amount of yarn as its counterpart. Which you choose to alter is an aesthetic choice for you as the knitter.
If you choose to make small holes, you will wish to alter the k-YO-p combination. After finishing the knit stitch, you will bring the yarn from back to front over the top of the right needle, and then proceed with the purl stitch. Work the p-YO-k combination as you usually would. Both YOs pass over the top of the needle only, and are the same length.
If you choose to make larger holes, you will wish to alter the p-YO-k combination. After finishing the purl stitch, take the yarn under the needle to the back, then bring it back to front over the top of the right needle, and then take it under the needle to the back again, and proceed with the knit stitch. Work the k-YO-p combination as you usually would. Both YOs pass under the needle, over the needle, and under the needle again, and are the same length.
In either case, the altered stitch will sit on the needle in the Eastern orientation, with the right leg behind the needle. On the subsequent row or round, you will need to work this stitch through the back leg to avoid twisting the YO closed; working into the right leg, regardless of whether it's in front of or behind the needle, is the rule to avoid twisted stitches.