Seriously, how do you do it? I've always been a big fan of delirium farming, and scarabs are money. I can get about 70 divines of scarabs from 38 divines worth of maps, but selling on TFT @ 85% ninja price, I'm getting just 60 divines. I understand that time is money and that I'm paying for convenience, but I'm leaving quite a bit of money on the table, especially since the ninja price doesn't take into account bulk pricing.
This isn't just about scarabs though - In general, how do you efficiently bulk sell straight to the trade website?
Time is money, so the reality is if you are seeing others consistently bulk sell on TFT at prices that are too low for you bulk wise, then you'll have to spend more time to get a sale. As for your actual question, simply price it per number like: public tab, set price for specific essence with currency type divine, then do something like 51/1 or 500/10 etc.