I would think the side of implantation had more to do with the month of conception and which side the egg was released from, but I don't really know much about it. I have heard that for the purposes of ultrasound scans, images can be flipped so are not always accurate, so try not to worry too much on that score. (Although like I say I don't really know)
The bio-rhythm thing, I can't remember if I commented before about it. I looked at that when preg with DS4 and it said boy. Never did it for the others, couldn't remember exact conception dates (it's been 9 years since I got ds1s bfp and then i fell first month so wasn't obsessing over dates)