Turns out my carbs didn't need much soaking at all, but they were full of 'mud'. The inlet filters were nearly packed with black material. A little simple green, worked a treat, and compressed air ensured that all my passages open. Thank you for the warnings about over soaking.
I do have another question though. On one carb, the cold start pistons are immovable. I didn't apply much force as I believe if they are stuck down then I'm good to go. On the other carb, they move freely and I reassembled them as they should be. I, of course, do not have choke levers on these so they shouldn't operate anyway. Before I reinstall the carbs in the car, should I disable the cold start circuits so they don't dribble gas when I don't want it, or I am ok with one stuck down and one free to move (with no way to move it)?
BTW the carbs had not been used much as I switched to a single carb due to overly restrictive heads (the dual carbs made no difference). But they had sat with gas in them, my fault, for twenty years.
Dean
1971 Super Beetle 1915 cc Dual Weber 44 IDF