I've thought about this a lot, the thing that troubles me with it is it seems to increase your required win rate a lot.
You buy 2 lots, 20 pips stop (net risk 1%) and take profit on 1 lot at 1:1 RR.
You have secured 0.5% and then you breakeven the 1 lot.
If your break even stop hits, you have realised a 2:1 risk:reward.
Assuming the second trade does well and takes a profit for 80 pips, you have gained x4 half risk + 1x half risk = 2.5% for 1% risked.
So, when hitting 1:4 RR, you make 1:2.5 RR and this is in the area of an ideal scenario.
It seems rather inefficient as a pay off for catching such a good move when you'd get the same return on banking 50 pips on the full position.
I wonder how well it would pan out long term when you lose full risk on all losing positions and gain only half risk on many winning positions and have a max pay off coming under 1:3.
This seems like it'd require a fairly high win rate to be overall profitable.