I think Easter weekend is one of the busiest times in Orlando theme parks so I doubt it will matter much WHICH day you go, it will be busy and the queues will be long.
If you must go I would suggest getting there as it opens and go round the park ANTI clockwise (most people go clockwise), or go directly to the BACK of the park.
That way you may get an hour or an hour and half on the rides before it gets so crowded it will hardly be worth bothering to queue.
I went to IOA a few years ago and it was indeed an amazing park. But one of the days we were there (February) was Presidents Day, and the queues were so long we did not bother to queue and just enjoyed being in the park (and went to some of the shows).
A better suggestion would be to dip out going to IOA that weekend (it will be horrendous) and go to Sea World instead. This relies less on queueing for rides and more on shows you are likely to see more (it was my favorite park).
And the Shamu killer whale show is one of the greatest things I have seen in my life.
See here
https://www.youtube.com/watch?v=HAfTHFiiNF8