I did the slow speed shifting with both the 205, and 203 with great success behind a manual trans. Never had a 208 or 241, so i can't say, but I did have a 203 behind a th350, and I couldn't get it to work.
The trick with the manual is, like you said, to get the engine speed to the gear speed so going from HI to LOW you have to rev the engine a little, you can practice to get it right, I used to shift through all my gears in a manual with no clutch just by matching speed of tires to engine.
With the Auto, the shaft even in neutral will still be spinning but you can't really controll it's speed so it's best to stop.
The trick with the manual is, like you said, to get the engine speed to the gear speed so going from HI to LOW you have to rev the engine a little, you can practice to get it right, I used to shift through all my gears in a manual with no clutch just by matching speed of tires to engine.
With the Auto, the shaft even in neutral will still be spinning but you can't really controll it's speed so it's best to stop.
