RCD mag pick up braket

BBC with a RCD mag pickup adjustable holder. For those that do not have a grid but would like to make small timing changes quickly between rounds........is there a holder with a "screw" adjustment to move the pickup location accurately? With the RCD crank support it is difficult to see to get the adjustment correct.
thanks

 

To clarify.....this is just to adjust the static timing.....no down track adjusting.