Best of 2024 video. Based on you asked about Portables
1- Add up all the watts of everything you would like to run during a brownout. EG: 5 x lightbulbs x 9 Watts = 45 Watts, LapTop = 70 Watts. large desktop gaming system 500 Watts, Coffee machine 1000 Watts, refrigerator 400 Watts...TOTAL = 2015 Watts............... you will need a 2300 Watt Generator. There can be other unforeseen future needs as you may add appliances, have company over with devices and you find you want to run an air conditioner along with multiple fans, then your need can easily bump to 5000 Watt Gen. to a 12000 Watt Gen. From just what you mention a 5000 Watt may suffice you nicely!!
2. Yes.......Some Generators have auto start but most require an Auto start switch . You still have to switch manually your breaker and or utility switch to cross the power over. Suggest you manually switch on the Gen after all you will have to ensure the Gen. has fuel and of coarse oil and you can always do a visual check that all is good. / Same for shutting off you manually need to switch breaker back and or utility switch back. And again do a visual check of your Gen, fuel leak? Oil leak? Components are dry ETC.
3. Ensure always whom you hire to set the system up in your home has licence, references and experience in doing so as per any fire insurance requirements if applicable.