Are there any known patterns when Emirates releases more business class seats for upgrading with Skyward miles?

Hi all,

I am travelling MEL-DXB later this year (oct/nov)
Have booked Econ flights
Trying to upgrade using skyward miles, but “no upgrades available” (obviously if I wanted to upgrade with cash they will let me)

unfortunately don’t have enough miles to book award seats outright

A chunk of my miles are expiring this year in May

Loads of seats are available when checked on ExpertFlyer/SeatGuru

What are people’s typical experience in when upgrade flights become available on EK?

Any ideas?