My two cents, seeing as you are interested in EE1, try it in Yr 11 and see how you go. You could always drop it in Yr 12. Though if you'd like, you could do another w unit subject with ee1 the 13th unit to give you a more customisable yr 12. (I did this in yr 11 with EE1 as a thirteenth unit)
I actually found in Yr 12 for a 1 unit subject the workload to not be too bad. Especially as you sit in your module, Yr 11 was more work as we jumped topics way more lol. I spent way, way more time on Adv and EE2. EE1 has nice scaling, and I did not find the work bad for the subject. Having an hour for the creative and an hour for the essay is actually nicer than being a 40 minute jumping rabbit than in Adv.