You're welcome for the help. I would always go X if you can afford it. That way when you move them to the garage or spare room you still have great sounding speakers. I have used stands for the front and rear. I'm serious getting speakers out and up will make a huge upgrade. So good for you on getting a set of stands for rear.
Here are some other thoughts for you.
Consider getting a Center shelf $17 to move the center down. It's small but it could make a difference. Of course if it sounds good you can totally leave it alone.
For the fronts I would move them out as far as you can go. I would also move them to the very front of the shelf. This will allow less interference with the shelf and allow port to have more room out back. The height of the mains looks good though.
Another FYI the Pioneers, Elac and Fluance wouldn't fit in your entertainment center like the Micca's do. So I think you're good keeping them for now.
Some thoughs:
I really like the those stands. They do very well with the MB42X. High value product.
You need to lower the speakers by about 3 inches or so. Have the speakers about at ear level when sitting or you can mid screen placement. Either one would be lower than you currently have them.
I would move the movies down and put the right speaker on the other side of the move case. You'll get more separation and no obstructions.
I would consider getting a center speaker shelf $25 to get it closer to the TV. If you don't want to go that route consider angling it up slightly toward the viewing area.
I got this mount a week ago and it's been working perfectly
Would something like this work?