From my point of view for this mission, you should use pres 4 as mengsk. The reason is on Pres 4 you can turn your army into a much stronger army and not need too much attention for every wave incoming while you can instant kill every wave. Next up is bombardment, I would prefer not to build any of them at all because there are 3 ways and they have air units too so not a great one (also the range is a big problem too). Finally, mengsk is one of those champs that can deal with super early waves and you need fast upgrade so you should try to start with drop bunker -> turn to worker -> 21 workers -> build bunker -> 2 gas full -> 11 troops with upgrade guns open base 2 if wave incoming turn back for defend then open base 2 -> drop bunker whenever you can and build 2nd bc (meanwhile spawn troop and build bunker if need take them to deal with a wave then turn them back to workers to build bc) so if you can do fast enough at 8-10 mins you already on 2 bases with a hell of army and money for anything else you one. one final touch you should try to use Imperial Witness on 2 bases and 1 more for your army then mana gain will stay around 200-230 you can play for days.
From my point of view for this mission, you should use pres 4 as mengsk. The reason is on Pres 4 you can turn your army into a much stronger army and not need too much attention for every wave incoming while you can instant kill every wave. Next up is bombardment, I would prefer not to build any of them at all because there are 3 ways and they have air units too so not a great one (also the range is a big problem too). Finally, mengsk is one of those champs that can deal with super early waves and you need fast upgrade so you should try to start with drop bunker -> turn to worker -> 21 workers -> build bunker -> 2 gas full -> 11 troops with upgrade guns open base 2 if wave incoming turn back for defend then open base 2 -> drop bunker whenever you can and build 2nd bc (meanwhile spawn troop and build bunker if need take them to deal with a wave then turn them back to workers to build bc) so if you can do fast enough at 8-10 mins you already on 2 bases with a hell of army and money for anything else you one. one final touch you should try to use Imperial Witness on 2 bases and 1 more for your army then mana gain will stay around 200-230 you can play for days.