Global spell tactics ?

[Boron]

After reading the most powerful spells thread i am now curious about your habits concerning globals and dispelling .

A) Which globals are your favourite ones ?
My 2 favourites are FotA and GoH .

B) How many gems do you usually invest in your more important globals you would like to have up for a while ?
When do you cast them ? Do you make them perhaps even a research priority ?

C) How do you normally dispel ? Do you try first with something like only +10-20 gems or with more ? How do you change your habits in lategame ?

D) If your global with only base costs got dispelled can you bring it up again with only using base costs ( if there is still a slot free ) ?
Would you rather try a 999 gem casting of e.g. GoH or Arcane Nexus etc. in lategame or always use something like 355 extra gems hoping your enemies try dispelling it with 500 or more gems each time and this way wasting gems ?