this is a confidence question rather than a technique one.
i am dyslexic. spelling and i have never got on, and no amount of school or effort has changed that. i use the tools, i read things back, and things still get through, particularly in the evening when i am tired, which is exactly when i am on these sites.
what happens is that i spend close to an hour on a message that should take five minutes, checking it, reading it aloud, running it through things. and i still sometimes look at a sent message the next morning and find something in it.
and i cannot shake the idea that on a page of strangers, a message with mistakes in it reads as careless or as somebody who did not bother, which is close to the opposite of the truth.
so from the receiving side: do you notice? does it change what you think of the person? and does anyone put something in their profile about it, or does that make it into a bigger thing than it needs to be.