seam sealer

Yes, another question. I just welded in a new inner apron (the one in the engine compartment where the battery tray goes) What is the best type of seam sealer to use? Please recommend a brand. I bought a tube of 3M, but before I use it, I wanted to make sure this is the best. I am not concerned about it being "factory correct" as I am building a driver, not a show car.
 
I did not know seam sealer was used on the inner apron. When I replaced mine I did not notice it having any. I just used a good quality weld through primer to keep the rust from returning inbetween the spot welded joints. 3M makes high quality products.