Can I do some multiple tags without leaving a "stray" letter/tag on the line?
Yes, and I'm so glad you asked. Stray tags have been showing up in some of your posts in birthday topics, but if you quote some of those posts that now include an admin note, you can check out the rewritten codes.
When using the code for center (or move), they must wrap around all other codes, like this:
[center][font=?][size=?][color=?][b]TEXT[/b][/color][/size][/font][/center]
This is incorrect placement and will cause a stray tag because the bold tags are outside the center tags:
[b][center]TEXT[/center][/b]
The same will happen to font, size, or color codes that are written outside of any center tags. Tags for move also need to be the outermost code.
Also, codes for center (and move) will continue to work for multiple lines of text and images, so it's not necessary to repeat them. For example, this entire post will be centered using just the one set of center tags:
[center][color=?][font=?][size=?]TEXT
TEXT
IMAGE
TEXT[/size][/font][/color]
IMAGE IMAGE IMAGE[/center]
Since codes for color, size, and bold will not work on images, they were placed after the last line of text.
I hope that helped, and happy holidays!