If you're talking about the deck front to back, that is what I call, deck rake.... you really measure the blades in the deck, front to back, I like the front 1/8" to 3/16" lower then the back.....this is blades, not the deck!
Also, the bottom of the deck all packed full of grass, will not mow right either....even if you have sharp blades!
Too much attack angle will cause the grass to be short at the front of the cutting circle of each blade & long at the sides so when you do a couple of runs you have a wavey looking lawn.
If the left & right blades do not overlap there is no way they can cut the entire width of the deck.
As new decks are designed the amount of blade overlap is being reduced which is good for the mower company as you will replace your blades a lot more often and the actual blades will be shorter so cheaper to make.
Really old decks have a full inch or more of overlap
Modern decks have 1/4" of overlap so when you have worn 1/16" off the end of each blade they will leave a strip of uncut grass between them
