Tier 2 (General) to Tier 5 (Youth Mobility) / extension?

I have been living in the UK for over 10 years and more than half of my life. I have considered applying for ILR through 10 years long residence with the support of I have been living in the UK for more than half of my live and a privately owned property, however, my total out of country dates exceeds quite a lot from the 540 days limit, due to various reasons, e.g. weddings/funerals, school/business trips, graduation trip, family holiday etc etc. According to my own record, I should be eligible to apply for ILR through 10 years long residence in September 2017, when the total out of country days will then be under 540 days.

Currently I am on Tier 2 (General) visa and it is due to expire in October 2016. Unfortunately, I am at risk to be made redundant. If the redundancy is going to be announced, it is going to happen very soon, before my current Tier 2 (General) visa expires.

I am not sure what are the options to allow me to remain in the UK legally and lawfully until September 2017, when I can then apply for ILR through 10 years long residence.

Because of my job nature, it is very difficult to find another sponsor. So instead of trying to find another sponsor for another Tier 2 (General) visa, can I leave the country towards the end of the 60 days(?) grace period from the Tier 2 (General) visa, and immediately apply for Tier 5 (Youth Mobility), which should hopefully allow me to return to the UK in 3-4 weeks, and remain in the UK for a further 24months?

Or can I apply for a 2 year extension based on 10 years long residence before / after I have been made redundant?

What is your nationality?

Have you had a Tier 5 YMS visa previously for the UK?

I have a British National (Overseas) passport, and previously had Student entry clearance (before PBT existed), Tier 4 (Student), Tier 1 (Post-Study Work), and currently, Tier 2 (General).

I haven't applied for UK working holiday (before PBT) or any other PBT visas apart from those above.

Thanks.

What country are you from?

Hong Kong

You would need to meet the requirements, but if you can, it should be ok.

https://www.gov.uk/tier-5-youth-mobility/eligibility

What is your occupation?

Thank you.

I am currently working in Procurement / Buying.

Would I need to apply for Tier 5 (YMS) within the 60 days grace period of Tier 2? or I can used up the 60 days first, like leaving the country on the 59th day and apply online on the 61st day?

What does the 30 years old eligibility actually mean? The site doesn't seem to be very clear about this. I will be 30 when I submit the application online, can the intended to travel date be when I have already turned 31?