What is the most efficient way to install my new outlets?
Conduit is allowed on the surface, most cable types would require protection.
You can run multiple circuits in one conduit, the NEC has derating requirements that generally limit you to 4 @240v circuits. 8 circuits is 16 current carriers, gets you 50% rating, which is problematic. It can be overcome with #10 wire on 20A circuits, but won't go down that rabbit trail unless asked.
If just straight 240v 20A circuits (without neutrals) the wires could fit 4 circuits of #12 wires in 1/2&quot; conduit, but you will probably find it easier to push the wire through 3/4&quot; conduits.
If you do run in just 2 conduits you would have box fill limits to consider. The calculation can be a bit confusing, but the minimum size box needed for the first receptacle location if you pull extra wires straight through, using grounding raceway, covers, and devices could be as small as 22.5 in³ (8 conductors, 2 for single device yoke, x 2.25 in³ for #12). Depending on cover used you might be able to get away with a 4²x 1.5&quot; deep box, but you best be considering at least 2&quot; deep, and then you probably could fit two devices per 4² box.
You could reduce conduit and box size after the first receptacle, but uniformity has appearance benefits without much sacrifice of space or cost.