>>535789037
Well there's a max size for a sphere and the starter star is actually pretty small so not all that long depending on how many rockets/sails you can fire up at once. Red and Blue giants would take a very long time and would require some insane production to get done at any reasonable speed. This is an O class star and took a long time but even it's not anywhere close to as large as a giant.
>>535789167
Dyson sphere program