Just about every tatter I know personally, is someone I taught to tat. It's kind of like teaching someone to drive. Your habits, good or bad, become theirs.
I've been tatting rather prolifically, for a lot of years, over 30 anyway. There aren't enough tatters nearby to have a regular frequent get together. Once a year, isn't enough to effect changes in the way I tat. I'm pretty set in my ways. I'm not a granny sitting in a rocking chair that's too old to change. I'm also not too stubborn to change when I see a reason to.
Since I don't have a local tatting group to bounce ideas around with, a lot of what I know and what I learn comes from the on-line community. Sometimes I see different aspects of tatting being presented in such a way that it suggests that tatters who don't do things that way are doing it wrong.Being a very independent sort or person my reaction is 'who says?'
So just to give equal time to people who may do things differently, here's my perspective.
Front side/back side - I don't do it. I personally don't think it looks any better than tatting it half and half. I just don't. So I'm not about to jump through hoops to keep all of my stitches the same way around. To re-train myself to switch each time I RW would slow me down and I have too many designs spinning around in my head that need to get tatted and put down on paper. Besides, do a 3D Daffodil and which is the front, the inside of the outside of the flower? The top of the bottom of the base. How about a carnation? See? it gets nuts trying to figure out which side it up.
Sometimes I do front side/back side tatting (confused? so am I). When I'm working a design with multiple split rings joining together I work them so that they are all the same way up. The juxtaposition of multiple rings connecting to the same point with some of the rings, or some parts of some rings not all the same way around drives me nuts.
Counting the join as the first half of the next stitch. - I don't do this one either. To me, a join is a join and a stitch is a stitch. I have been successfully tatting anything and everything for years making a join and then a full stitch and my lace looks just fine, thank you very much.
Posting the shuttle through the ring before closing it. Tried it once. My other closed rings looked fine, the one where I posted the shuttle through looked twisted and I had to open the ring up so that I could put the shuttle back through. I have too much tatting to do to try that one again.
Tatting proficiency? Hmmm. Definition PROFICIENT skilled or expert. 30 years of tatting and teaching others to tat, 10 years of designing and publishing patterns, I guess that qualifies.
If not, I'm sure the tatting police will soon be at my door for spreading sedition. They're welcome, I'll just put the kettle and while they're peacefully sipping tea I'll wrap them in tatting so they can't get away. I'm sure they'll come around to my way of thinking eventually.