Do you plan to play the NT or DT spot?
For a DT, I'd personally go with the FS piece and spend the SP to raise your shed block throughout your career. In my opinion, the 20-25 SP you'll spend to get Shed from 6-10 (which you probably wouldn't need to do if you go with the shed block piece) is worth it for the ability to add some differentiation and new bonuses to your player with FS AEQ or something else like Blitz. FS looks like a really solid addition to a DT at this point if you ever plan to get your speed above 60.
Think about this. Later on you might see a second FS piece and then you'll be able to have 8-10 in FS. With 8 FS and enough speed you'll be very hard to handle. Basically, the faster you are, the better you'll be in run support. There's a reason you don't see too many NTs with more than 50 tackles - it's because they're slow and spend their whole game fighting a center, breaking a block, getting reblocked, then fighting again while the HB runs past them. They serve their purpose of making the HB choose a different path, but they rarely get off their blocker and can't get away from him quickly enough to chase down the HB, which is something a faster NT/DT can do.
The way I go about choosing AEQ is to try to keep my player flexible because of the way the sim is constantly changing. I build my core player, then use EQ to fit the current sim. You know you're always going to want high Shed Block, so I don't see spending the SP to buy the higher points of Shed as a waste. Others will say you can save a lot of SP by getting the Shed piece, but I think having the flexibility to add new bonuses that fit your build is worth it.
Now, if you plan to play NT your whole career, then maybe the Shed piece would be a better choice because you might want to focus on the run tree and spend your SP there. You have to think about the opportunity costs and where you'll be at level 50 or so.