You never said how big a generator you have. The switch you mentioned should work fine as long as you only have 6 circuits that you want to power and none are over 20 amp. Furnace, fridge, freezer, TV/stereo, well pump, sump pump, coffee maker, stove.
Pig tails work fine but power companies tend to frown on them due to the risk of backfeeding the main, and they may not be legal in some areas. For a little more money you can install a whole house transfer switch (manual or automatic). They install between the meter and main breaker panel and switch between grid or generator power. That way you can run anything in the house as long as you do not exceed the generator capacity.
