VHS to DVD: Media type & speed

Most of my VCR's were recorded on the lowest quality (longest record time) possible: 6 - 8 hours per tape.

What record speed should I uses for the DVD recorder?

Is there a media preference? DVD +R, DVD-R or DVD-RW?

I will be recording on a Samsung DVD-VR 357 standalone DVD/VCR record & play unit.