Tier 5 (YMS) from a Tier 4 student visa.

Hi all.
My girlfriend is Canadian, we've been together three years and lived together for the last year and a half. Her Tier 4 student visa runs out at the end of the month and shes moving home on the 29th.
The visa most applicable to her seems to be the tier 5 youth mobility visa, the plan is to apply for this.

My question is how long will she have to be outside of the UK before she can re-enter, as far as i can tell, there is no limit, and the only limit on applying for the tier 5 youth mobility is that
1) you haven't held a tier 5 before
2) you apply no more than 6 months in advance
3) you are not within the UKs borders when you apply.

So the plan is, she leaves, applies for the Tier 5 immediately with a start date for the visa of around a month later. Can anyone confirm if this is a correct understanding of the application process?

Thanks
Daniel