I've planned something for the office, and want to be sure everything is fine, can you confirm?

Hi! I'm working in an office where we do cinema/television post-prod. I've studied programmation back in college, so did a bit of networking, but it's been a long time.

Long story short, the network is shit. Old cables and hardware, bottlenecks because of how the switch are connected together, it's bad. Espacially since we are working with big files.

I decided that it was time for a change, so I started updating my knowledge on networks, and I came up with something.

Here's some info:

• We have about 12 Mac Pros from 2013, with two 1Gb port each. They support lacp aggregation.
• We also have a Qnap NAS, with four 1Gb ports, also supports lacp.
• The office is separated in two sections, so we would like two switches, with 24 ports each.

What I want to do, is to run 2 cables for each computer to run them with LAG, and 4 for the NAS, with LAG too, to allow for faster file transfer everywhere. Half of the computers on each switch. I want to connect the switches with one or two 10Gb cables.

Here's what I though of:

2x S3900-24T4S Switches

2x or 4x Transceivers

1x or 2x Fiber Optic cable

Than a bunch of Cat6 cables to connect the rest.

Am I wrong? Is there something I don't know about that I should? Any advice? Will my idea with LAG work?

Thanks so much!