Practice on local field

Tonight I went over to Local Field and started to put into practice the new objectives -

• Bowl faster (use a run up).
• Flight the ball - spin it up above the eye line.
• Spot bowling (I'm using a 20" innertube).
• Bowl alternate Gipper-Wrong Un- Top spinner and Doosra.

I may change my mind on the Doosra as it involves a particularly vicious flick which is wearing on the muscles and joints? The first impression was that all of this looks pretty attainable - I think one of the issues that I have is judging the distance in front of the batsman as to where I need to pitch the ball. It's easy bowling into a tyre because it's so visible, take the tyre away and it's a lot more trickier. The other issue is the concentration factor - one of the things I've adopted recently is the awareness of the need to have the leading arm high at the point of starting the rotation, but I have to concentrate on doing this, which means concentration then lacks elsewhere in the short term until this becomes second nature. I'm now thinking in terms of - if the batsman adapts to my bowling in that he adopts the tactic of not trying to go for the short balls and instead steps back and hits it off the back foot, do I then need to bowl it a lot fuller and faster? This is where the Gipper would be good I reckon, but it requires that I'm aware that this is happening and adapt to it - I don't think I'm up to it yet?