I suspect all this is getting quite confusing for the OP.
For the record, I have a 12" f5 scope, and the eyepieces I mentioned (even the cheap LP ones) are well corrected for coma at that f-ratio, and give sharp images across virtually the whole field, so you can watch a planet pretty much from one edge of the field to the other without having to move it into the centre of the field for the whole time.
For visual use they do a great job, and are a lot cheaper than a Paracorr or an equatorial platform...
- Dean