I would be glad to help if I can, although SteveH is probably much better for the measurements.
My Weed dates to 1868 from what I can tell. The shuttle moves front to back very much like the Howe machines and is an open boat style shuttle. I have found that the Boye 18 needles work nicely and it isn't too complicated for threading. I have a copy of a later manual that was shared with me by another collector.
I can provide more photos if you like.
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