Here’s my solution:
Shifter with inner-most sprocket engaged.
Note amber 9-sp resin spacers between 8-sp sprockets and aluminum spacer inboard of the whole stack. Morning winter sun in the kitchen.
An 8-speed Campagnolo cassette is so fat that friction shifters (designed for narrower freewheels) have to be pulled all the way back to be parallel to the downtube to get the derailer to move over far enough to catch the inner-most sprocket. A very nice kludge is to replace the 8-sp spacers of your cassette with 9-sp spacers.
AFAIK, all Campag 8-sp cassettes had individual sprockets not riveted onto a carrier, so like Veloce 9-sp, which is where these spacers came from. The smallest sprocket will have 8-sp spacing because it has its own spacer but this won’t matter for friction.
The shifter is a (used) 8-sp Dura-Ace indexer set to the friction option (obviously.). With the original 8-sp spacers in the cassette, the lever throw is too long for convenient shifting but the 9s are nice. I actually prefer the finer finger movements to nail the gears with the narrower spacing.
Use a 9-sp. chain — Campag here.
Works really well.
Note my derailer is a proper cassette-era mech. I don’t know if an NR will swing in far enough, depends on your limit screw travel.