I used to struggle leg side as well. A coach advised me to get someone to do 'throw-downs' at my legs and just to focus on timing the ball as I used to try and play 'wristy' shots off my legs and ended up either hitting the ball very fine, missing the ball or getting a leading edge.
I did this for a while and once I was timing the ball well I had some more throw-downs but started to think about shot placement. Once I was comfortable and happy with the shots I was playing I then had the bowling machine set up fairly full on middle and leg/leg stump and practiced my new technique on that. It took a while to get rid of the old habits but it did work. I still do the whole practice from time to time if I notice a problem or don't feel comfortable during an innings.
You need to get your front foot to the onside of where you think the ball is pitching very early, do not think twice, just get it there as soon as you see it going down legside and wait. From this position you can get a full face of the bat on the ball by driving it. Obviously the wider the ball is the squarer facing you will end up, do not worry about this.