dyetim1 Opening multiple tabs is helpful when you wish to play with auto on different coins. So the time spent while playing on 1 coin is spent on playing on 10 coins.
Of course, there is always the risk of busting on all 10 coins
The response speed will actually depend on the configuration of your computer. Most browsers will crash when you have a lot of tabs open, which is irrespective of whichever site you are accessing via them. There are a few steps which will enable you to open more of LG that is switching on the ECO mode, and accessing rare win bets rather than my bets. The lesser information updates on a page the lesser load it will be on your system.
As for your level up doubt. It will only help till your betting level - Depends on the total bets count. Maximum 100,000 Points (10,000,000 bets) is achieved. After that the it will all depend on your wagering amount - Depends on the total wagered amount. Maximum 100,000 Points (100 BTC).