Lightroom LR 3.4.1 Exporting Megapixels and Croping & Resizing

Question

I crop in most of my images.  After exporting at Image Sizing/Resize To Fit UNChecked, JPG, 100% Quality, and dpi 300, my cropped images are way below the normal non cropped images size.
So, I recently started trying using resize to fit, selecting megapixels, and setting that to 12.2, and the file sizes increased back to normal uncropped sizes.
12.2 is my sensor size, so I thought it was not really losing any info.
My question is whether this is a good way to resize for prints up to at least 13X19 if needed?
I know Elements has a resize (haven't used it) but in the workflow, I'd like to stay with LR if possible.
Is it decent resizing?
Thanks
Michael

Answer 1

Thanks Ian.
That's a little scary because I can crop anything from 50% to reaching a couple of soccer players across field (even with my 70-200) and the cropped image could be 25% of the total image (sometimes slightly smaller).
?Would it be fair to say that since I am starting with a 12mp camera, that a 50% crop, and resizing by the megapixel choice, would be the approximate quality of a 6mp camera, and still give a good 8X10 or even 11X14?
That brings up another question.
?When I do choose megapixels as my resizing choice, and given my using 25%-50% of the image in a crop, should I choose 6mp instead of the 12mp that it was originally shot at?
I have been using 12mp as the size I wanted (simply to try to get it back to my camera size), and now I don't know what that quality looks like when my soccer customers placed their orders.  They have order from 4X5 to 8X10's already, probably from a variety of crops.
Michael