What equipment are using shooting your pics with, Mike?
If you want to keep the core looking good and not blown out, try taking some short subs of 5-10 secs in length, but don't go much higher than that. The core is that bright it will blow out on longer subs. You can then blend the short subs into longer subs of the outer regions to produce your piccies. Also, don't go heavy on the sharpening filters, that can make your piccie look a little too cartoonish by giving it an embossed look. Too much sharpening can also produce dark rings around the brighter stars as well.
Another thing, be careful when you attach your camera to your scope. See how you have eggy looking stars over a lot of your piccie but there's a patch on the right where they're not too bad...your camera is not square with your light path and it's probably pinched a bit as well. It's just a matter of playing around with how your camera is sitting in the scope. You might need a slight shim on one side to get the chip square with the light path. Once that's done, any eggy stars from then one will be a matter of guiding errors rather than anything mechanical (hopefully). Another thing which can give you eggy stars is having a curved FoV across the chip, but it's best to deal with the easier stuff first before you go looking at field curvature and correcting that...which depends on what type of scope you're using (i.e. the optics).
Hope that helps
