a few quickies, thanks to anyone for an answer ...

has anyone experimented with placing the grooved sides away from each other, is there an upside-down to the lenses that someone has found?

how picky is fresnel positioning, i know optics very well, but the fresnels should be a little less intense in projecting positioning flaws...it will be easier in my box to mount permanently, but harder to position perfectly.

i'm especially concerned with top-bottom tilting (like keystone tilting), the LCD as well.

thanks.

Assuming you get the fresnel's positioned properly from the light source and from the triplet, you should be in good shape. Just keep the recommended distances between them and the lcd panel or you may end up with circular lines in the projected image.