That will set the limit for a single buy.
Some nice strategies allow multiple consecutive buys, when the conditions are met.
Often, there are 4-5 buys before a sell is complete.
But sometimes, usually when the price keeps falling, I can wake up to 20 buys and a huge bag.
Is there some way I can set a hard limit for how much a pair can execute buys?
As per your example, 
binance": {
            "USDT-BTC": {
                "strategy": "Base_USDT",
                "enabled": true,
                "override": {
                    "TRADING_LIMIT": 150
              
SMACROSS will buy 150 USDT in BTC each time. But when done 20 times, that will come up with 3000 invested in 1 trade.
It would be great to be able to set a certain amount, say 1000, that would disable the future buys until the Sell is made.