OOPs!!
Should have made you cut at the top crown! O'well, to late now. Get your blue tape there in the photo and start at the front of the 1/4. Stick it good to the front and pull al the way to the rear of the 1/4 without it sticking to the panel, pull the tape as tight as you can and stick the rear once you get an eyebell down the 1/4. I would start above the line (tape below the bodyline). Get some evercoat metal glaze and mix it cold! Start at the front and drag the glaze with at least a 6" spreader to the rear of the 1/4. Try to get this done in one or two strokes. Firm-flat pressure on the spreader. Once done pull the tape and let the glaze kick. Use a good flat block and knock the sticky surface of the glaze off. Just the sticky surface, don't block out yet! Stay off the bodyline!!
Start over again on the bottom of the line and apply the same blue tape and repeat the above instructions with the glaze (tape above the bodyline).
Once the glaze has cured about 30 minutes spray a light guidecoat of cheap rattle can flat black then get a 12-18 inch flat block and start sanding in a "X" pattern towards the bodyline. One side at a time!!!! If it makes you comfortable apply the tape to the side you are NOT sanding. I would use 180 grit and work in long light strokes.
You can pefect the bodyline once the filler primer is applied!! Use the tape again after you prime and use the same method as above to sharpen the line.
Remember!!!!!! "X" pattern towards the line!!! STAY OFF of the bodyline when sanding. Take your time! You'll get it!