being concave has to be some type of 5p. You just have to run stripper passes on the side to fill it up. Also, make sure you have it a little above flush on the side before you cap. You might also be running too hot, that'll make it concave, too.
On the bead, just drag it, no need to whip going downhill.
Some places will make you run a one bead cap, kinda hard to do on 6G and make it look good. It depends how wide the bevel is.