I did mine myself. I didn't take as much time as I should have because I had a hunt coming up quickly and had a very small section of time to get it done. If I had a solid 3 hours to dedicate to it I could have done it really well by taping off the seams then sealing them, and pulling the tape off prior to the sealer drying. However, I just painted it on and hoped for the best. It is functional, but doesn't look the best, that doesn't really bother me though.
If you decide to do it yourself, order extra seam sealer. It said 1 tube would do it, I bought 2 extra tubes, and that was just about right to get it done and have a little extra in case I missed some. Mine is the Little Bug Out base/tarp/vestibule.