Biggest suggestion I can do to help you out is to start hitting the training dummy to figure out the best ca sequence for you. A lot of timing is gonna have to do with your haste mod. The auto attack bar is a big need for you to be able to time your cas you can also use ACT (
Advanced Combat Tracker -- An Encounter Parser for EQ2) to put a sound in when your auto attack goes off. Simply put the more haste you have and the shorter the delay on your weapon the less time you have to spam cas w/o missing your auto attack. As your epic weapon/mythical is a 3.0 delay weapon I would suggest you get used to that delay early on.
For casting order like I said test it out see what you like the most as you get more aas you will also get more abilities that you will be cycling into your ca order so your best bet is like I said hit the dummy and act will be invaluable to you finding out what works. Work thru a few different orders see how your dps is on each order then start analyzing the pie chart seeing what attacks did what percentage of the encounter dps. You may also wanna have some practice aoe runs on act to get an aoe cast order down which can be easily done just by placing multiple dummies how an encounter would usually position itself.
Overall your cast order will be changing a lot as you get new cas aa abilities and eventually your myth. But with practice and a lot of analyzing you will find what works best for you. This game has a lot of ways to skin the cat so don't limit yourself to what works for others try it out for yourself and see what fits your style. Grats and your zerker and hope this helped you out a bit.