Don't do either of those. If you need to pass VLANs between the switches then they should be Layer 2 Trunks between the switches. If you need to exchange routing information you should connect P2P links between the switches and have them participate in your routing protocol.
Are all of your Aggregation switches connected in a mesh or are they in a series? What topology has you using 5 - 10 Aggregation switches? If you need this many switches you probably need a bigger switch. :)
In an idea scenario you would have 2 - 4 aggregation switches hosting the SVIs for your local data center. These numbers are fully dependent on the number of downstream switches that are required in each row. Then these aggregation switches would connect up to your core switches via Layer 3 Links.
You will run in to all sorts of issues if you try to implement what you are describing. Let us know more information about your scenario and we may be able to assist you further.
The reason the switch models matter is because a detailed design will always be limited by the functionality of the devices that will be implemented. After doing some quick research on the Dell website I see that the S6000 switches are both stack and VLT capable. So here we have two paths to a more flexible and maintainable design.
If you stack the S6000 switches in the core they will become one switch with multiple modules. (Similar to a chassis switch, see this.) At this point you can configure links from both core switches to each aggregation switch in a non-blocking manner.
With VLT on the S6000 series you are able to configure an LACP Port-Channel from both of the core switches to each of the aggregation switches. They will appear to each aggregation switch as a single switch.
If your goal is to achieve Layer 3 at the "Aggregation" layer that you have described then the stack is your only option. You will not be able to create Layer 3 Port-Channel interfaces using VLT.