pH of 6 is ok for clover (a bit higher wouldn't hurt). you do not want to put down much, if any nitrogen with clover (P is most important nutrient at planting). as far as types of clover, there are hundreds to choose from. I would check with the local ag agent in your area and see what the farmers are planting in their pastures (prefereably rotational grazers). I would definitely say you wan to go with a pasture variety of Ladino clover and possibly a little red clover. I have used Alice and it is great (grew nice, tall, huge leaves. Jumbo is another variety I have used and like. Godd luck.