Crictech sheets are well worth the investment as getting your middle in the wrong place is expensive! I moved to a slow low deck and brought a lower middle bat. When I re-did my crictech sheets, the ball placement had moved only fractionally down from the normal high spot on the bat - certainly not enough to make a difference in middle position. In short you hit the ball in the same place through technique more than conditions.
If you can't get a crictech sheet quickly (I would recommend crictech first, doing it the scientific way), just clean you scuff sheet on your existing bat and then wet some red cricket balls a little bit. Hopefully the red dye will stick to the scuff and provide a DIY crictech alternative.