Extend the TX Buffers to 4
Once the TX Buffer is completely present in the SRAM, and it is completely prioritized, it should be extended to 4 Buffers. It might be even good to think whether not to create a generic amount of buffer (e.g. 2,3 or 4).
This should play along nicely with the buffer prioritization. If the logic vectors are implemented in generic amount, then the extension should be no problem at all!