There are design ideas that make the difference in how the siphon will work. A larger tube to carry the water away will let more water go out so it does make it seem stronger. But at the same time running the same diameter all the way from end to end like just straight tubing will not work as well for many of us as what we see on the ready made units that have an extra large portion at the pickup end. What I find best is having the large area and holding it just above the substrate. This will pick up the loose stuff as well as some of the sand. But the large area lets the sand swirl around and drop back while the light dirt portion goes on out. Kind of self sorting the debris? If you use a larger diameter tube, you will get more volume flow but that can also mean you pour a bunch of the substrate out in the yard or drain.
To get the most "power" one might want to use a small tube at the pickup and larger from there on but most would not like that as it tends to have too fast flow and pick up stuff when you don't want it picked up. Things like small fish, plants, etc?
My favorite water wand is this el cheapo. I add enough tubing to press fit on the end to run to the drain.
It has a squeeze bulb to start the flow very easy as well as a good design to let me get down into the gravel if I want as well as the large section to sort out the sand. There is also a grid over the end to stop it if I run it across the top of some fry that I don't notice.