RE: Proper technique for 2 excersises?
Belt - 2 sides for this arguement
Some say best to have it to support back
Some say best not to as it'll encourage back top go strong.
I don't and good for 240kg. (buit saying that I was careless the other day and hurt it when repping 220kg, but I doubt a belt would have helped)
As for speed, there are LOTS of ways of doing things. I'd just recommend steady and controlled. You shouldn't be able to throw weights around as it should be too heavy, but you should be able to lift controlled and keep form. So just do it steady and controlled, anmd get a rull ROM (range of movement)
Raw dead Lift 320kg
Raw bench 171kg
Shirted bench 200kg
Amateur cage fighter @ 95 - 105kg