Tom, you want to set too much goals to your bees but bees not know about your ideas. Hive has it's own schedule to develope.
Syrup feeding helps your hive not at all. It just fill combs.
2 foundations are vain in the hive because bees cannot occupy the space.
They don't draw frames even if you want. They need not new combs.
The model how to get nuc bigger is simple:
When colony occupies one langstroth box, you need enough bees. Capped frame does not help at once because capping period is 2 weeks.
But if you give 2 full capped frames it produces 6 frames bees during 2 weeks.
And you cannot see if hive is "vigorous". After emerging it takes about 3 weeks untill bees start to fogage. So 2+3 weeks = over 1 month.
Some accelerating beefing helps but you have still summer there for long time.
"You want that they draw 2 foundations". Why you do that? If bees not want, why you force them do such.