Sorry Bb - of course I meant .25.   I was only trying to explain that a really high  min shading rate is not what you want.  I was only trying to help, in the absence of greater knowlege such as yours,  If I had realised you had already posted  a reply until after I had posted mine I would not have bothered.   There seems to be a major time lag in what is live in the US and the UK, so please make allowances.