Looks like you caught the mileage bug- it only goes downhill from here

Expertflyer.com (paid service) will allow you to search for Delta flights that have mileage upgrades available. You can also call Delta to ask about availability, but in my experience many agents look at the wrong buckets or automatically say "no upgrades available".

If you plan on flying a lot Expertflyer is an invaluable tool (at least for me). IT helps me when i SDC (which you get to do for free as a Gold or higher) as well as find out which flights have the most upgrade space, so I can book flights with the best chance of upgrades.

It also allows you to search Air France and Alitalia award space- which has been an invaluable resource.

My only advice to maximize your mileage would be to scratch Honolulu and head to Dubai or Singapore- go for Platinum!