Sending a hopper minecart over a furnace array on powered rails results in the furnaces alternating 3|2|3|2|3|2... items and I cannot reliably get them to transfer the same amount of items per furnace.

If I send it on powered rails over hoppers over furnaces, it alternates 7|5|7|5|7...

hopper minecart with option turned on tries to push item every tick, so it means its taking 3 / 2 ticks per block - yes, 8 block / second so its correct.
With hoppers, hoppers also tries to pull and hoppercart pushes. it will be more messy with curved rails.

Would it be possible to add a config that allowed us to control the tick speed that hoppers tried to push items?