Power supply test lead design questions
If it is NOT for (semi-)permanent setups, but it is for acutual "heavy-duty" bench work, I'd stay away from anything than silicone-rubber-insulated multi-stranded wires. If a hot soldering iron is around it is extremely easy to melt away a simple PVC insulation, and the fact that the positive and negative wires are kept so close together means a guarantee for nasty shorts if you are unlucky (especially if the power supply can deliver high current spikes).

Moreover, good silicone rubber insulation together with multi-strands makes your life better when handling wires on your bench: they don't stick to each other and to other wires (DMMS, scopes, etc.) and it is easier to move them around without dragging lots of things with them!

Moreover, these kind of wires are made to be moved all the time. Normal PVC insulation might not survive well the "hard life" of the bench top. You could end with an insulation with cracks and cuts that can fail you just in the worst possible moment.