Hi RC101,
My #1 V35 is the one without a working steel-ball detent. (I delved too far in my early investigations when the actual problem was the mis-assembled WA Focotar.)
Some time ago I swapped out the current lamp-holder from my #1 V35 into the #3 which I essentially bought as a "spares" package - knowing that it had the original lamp holder, but discovering the owner had ensured that the AF (with detent) worked properly. For a few months I've been working on modifying the original lamp-holder so as to take a current 13139 lamp, and two days ago I got #1 V35 working with a 13139 lamp, so this evening, I'll be able to check whether the AF drifts etc. (I won't be making any prints, but I have a number of grain focus finders, including a Peak and the larger Paterson.) I'll set it at max height, and check at various points, and return to max.
I'll put some effort now into getting its base level, and clearing a little space in my kitchen.
Some years ago there was a Leitz Valoy offered via eBay, and I was the only bidder! I got it for the eBay minimum bid of £0.99p! It was even delivered to me in Milton Keynes when the owner drove here for a job interview. Feeling somewhat embarrassed, I gave him £20 for his trouble. (I've never seen a 1c.)