How do I evenly distribute items between 4 furnaces without minecart?

The problem I'm having is evenly distributing cactus from my farm into my xp smelter. Because the cactus flows into the hopper minecart relatively slowly, it is filling the first furnace on the minecart track more than the others. I'd really like to do 5 or 6 or n furnaces, but I'll settle for a solution that involves 4.

One thing I tried was simply two hoppers underneath a chest, then 2 hoppers underneath each of the output chests (so 4 hoppers on this layer), but two of the furnaces filled up while two completely did not... something like an expansion of this.

Solution 1:

Solution works for JE and BE.

Solution Notes

• The top hoppers point sideways, including the last, which points into the side of the comparator.
• The hoppers just below the top line of hoppers points down into the furnaces.
• This solution works with up to 15 furnaces.

Downsides to This Solution

• When the machine finishes, up to one item could be stuck in the bottom hoppers. These will be flushed through into the system when the next load is entered into the machine.

How it Works

This section will show you how this machine works so you can apply the same principles to other situations!

1. Items flow one by one through the top hoppers.
2. By the time the first item enters the last top hopper, there will be one item in each top hopper.
3. When that happens, the repeater and redstone dust trail turns off, unlocking the bottom hoppers, allowing the items in the top hoppers to drop into their respective bottom hoppers, and into their furnaces.