Coin control must be enabled in options first, then it will be visible in your send tab.
IW
Set optimal input size to 10. In theory, optimal input size is even lower but 10 is good enough and is the lowest the client will allow you to set it anyway. Coinage is unlimited and you are gonna max out the reward everytime anyway. This maximizes the amount of weight you keep on the network at all times and minimizes the amount of weight you will need to spend to get each 16.18 coin reward. Trust me, keep your client online 24/7 and let you coins continue to accumulate weight for a month or two and it makes a HUGE difference to the amount of coins you stake.
There is no need for multiple addresses, it doesn't matter. I'd advise using coin control to manually break down your inputs a bit though to jump start things. Just keep optimal input size at 10 and within a month or two, you will have thousands upon thousands of very small inputs, like 10-30 coins each. This is exactly what you want to have.
I personally find leaving the wallet online only nets slightly more coins than if I stake 4 days on 4 days off.
As for auto CC, it will take a few months before your stacks start getting as small as you want them. Auto-optimize can only split the stacks in half each time it stakes if I remember correctly.
In the early days of XQN, right after the fork to drop the reward down to 16.18 XQN per block, I personally staked at least 75% of all blocks on the network for at least a 6 month time frame. I was most likely the only one staking staking this with the proper strategy.