Here's an example of a startup level ajustment event(taken from HSR v1.03c). Introduce a few global techs ajusting GD and the like and link them to a startup level ajustment event like this one, and you'll have difficulty levels included in your mod in a relatively easy manner.
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# Level adjusting GER 123910-12314
#########################################################################
event = {
id = 123910
country = GER
trigger = {
OR = {
AND = { ai = yes event = 123900 event = 123902 event = 123908 }
AND = { ai = yes event = 123901 event = 123905 }
AND = { ai = no event = 123900 event = 123902 }
}
}
date = { day = 2 month = january year = 1936 }
offset = 1
deathdate = { day = 30 month = december year = 1947 }
name = "Beginner Mode"
desc = "You have got the Beginner Mode for your country."
style = 0
action_a = { name = "Mr. Burns: distinguished"
command = { type = gain_tech which = 4000 }
command = { type = gain_tech which = 13000 }
command = { type = gain_tech which = 13004 }
command = { type = manpowerpool value = 3810 }
command = { type = supplies value = 22000 }
command = { type = oilpool value = 22000 }
command = { type = coalpool value = 22000 }
command = { type = rubberpool value = 22000 }
command = { type = steelpool value = 22000 }
command = { type = trigger which = 779 }
command = { type = gain_tech which = 4004 }