Anyway, the answer is yes. In fact, you should constantly adjust your lead speed to accommodate the changing environment you are fishing. Think of your approach as dynamic and each cast as a question. You have only found an answer when you connect to a fish. Ultimately lead speed is dictated by the current, the depth, the flies weight, and the fish behavior. Play with it until you dial it in. If you are confident there are fish present then keep tweaking. Just don't get stuck with hard and fast rules about lead speed. Good luck... and go fish.
The above just about sums it up.
The more you fish these techniques the quicker you will be able to read the water you are going to fish, and by definition of that reduce the time it will take you to figure out what is needed based on the flies you are using.
I have myself long lined with rods as much as 12ft in the past, which does provide way easier control at extreme range.
I well remember back in the early 90s watching some of the Czech guys who were fishing a International.
Before they fished the section they would walk it.
They would more or less know what they needed to fish the zones in that section. before a fly was cast.
Methodical to say the least and furthermore unbelievably focused, which for the majority of FF fishers is not the case, unless you are into the competition scene, for without that you are well and truly lost from the get go.
Simply as mentioned you have to be on the water to figure it out.
Davy