Are you using the crossbow version or the standard version? Not sure what, if any other than marketing, the difference is between the 2 so just curious. Been looking hard at these.
I’ve had the best luck with trace mineral salt blocks from rural king. ~$8 for a 50 lb block and I use about 2 per year. It’s a well established mineral site now and they visit year round but absolutely hammer it during lactation and velvet.