Using Flats in Astrophotography

So now I am a believer.  I know most are already using flats so this for those that are not.  They are pretty easy to take if you have a DSLR. After doing astrophotography for a couple years I have finally started using flats.  Not coming from a photography background they were always something of a mystery to of me.  I have read many directions on how to take them and tried them unsuccessfully last year.  For me what was missing was a video of someone actually doing it in the field.  That all changed a couple of weeks ago thanks to Trevor Jones from Astrobackyard.com.  His YouTube tutorial (How to take Flat Frames), as usual, was excellent especially since I was able to follow it.  Setting the DSLR on Av-mode and putting a T-shirt over the objective as he described worked o.k. on the Double Cluster image I took a few week back, however I don't think the sky was optimal.  He suggested getting a light box.  As luck would have it, Scott (https://www.astrobin.com/users/BigScott_27/) a user on Astrobin who happens to live really close to me saw my post and said he had a really nice light box (http://spike-a.com/flatfielders/) that is collecting dust.

The top image of the Soul Nebula is stacked without using flats and the bottom image is stacked with flats (taken using the light box).  I did about 5 minutes of the same processing on each for comparison, thus the only processing that was done after stacking was RGB set to 35, curve stretch, levels (except I used Gradient Exterminator on the image without flats).   The image is not done yet I still have much more processing left, however, it will be a lot easier to get a good image.