Basically, there are two approaches to the leeward mark. You can approach on starboard (best approach) or on port tack.
Starboard is preferred because you have inside room on all port tack boats and since you are the right-of-way boat, you also have the right to make a tactical mark rounding, i.e., enter wide and exit close to the mark.
But first, assume you are approaching on port tack. You need to steer below the mark so you can have a good tactical mark rounding. And for a standard spin drop (no Hooter or Snuffer System) the helmsman has to steer down deeper to create a vacuum for the spin to be doused. Which if fine because you do want to do an "enter wide, exit close" mark rounding.
Now we are back to the question you asked. Here you will have to let the mainsheet go, and bring the traveler center to prepare for the mark rounding.
At that point and while the spin is being dropped, your mainsail backside tell tales should be flowing.
As you begin to head up, you will need to sheet in at the same time (probably hand over hand -- in other words quickly). And you must sheet and steer at the same time. You cannot sheet and then steer, or steer and then sheet. You must develop a way to do both at the same time.
And you cannot use the mainsheet block's cleat -- every time you try to grab a handful of sheet you will have to look back at the block to find the sheet. But, you should be looking forward at the mark -- like a race car driver always has to look at the inside of the turn.
Some folks like to simply pull the traveler in with the sheet already pretty well sheeted, but this is not as effective and will make the sail stall more easily.., and then when the stall goes to lift, you get that 80% rush again.
Best to sheet in -- you will find the telltales behave much better and basically you are simply taking the twist off the sail while sheeting.
Now on the starboard approach, come to mark about two boat lengths out with normal sheeting. While you are initiating the jibe, the area too lee of the main will be a vacuum for the spin to come down. This time, however, you do not need to adjust the mainsheet.
In my seminars I teach folks to jibe with a certain pattern. Say you are on starboard tack. You begin the turn and work your way to the back of the boat, hand the tiller extension from your left hand to your right hand on the other side of the sheets. (don't change the adjustment of the sheet or traveler)
After you have the tiller ext. in your right hand, use your now free left hand to throw the sheets (and sail) to the starboard side, getting you on port tack.
That way you have your hand on the tiller at all times.
Once that is mastered, it really comes in handy for starboard approach mark roundings.
Here is how you do it:
Part of it is the same. You begin the turn and work your way to the back of the boat, hand the tiller extension from your left hand to your right hand on the other side of the sheets. (don't change the adjustment of the sheet).
[color:"red"] Here is the difference [/color]
After you have the tiller ext. in your right hand, use your now free left hand to pull the traveler to center.., instead of throwing the sheets. This has the same effect as throwing the sheets(and sail) to the starboard side, getting you on port tack. However, after the jibe you want to go to windward. The sail going to the other side will push your bow right up to nearly close hauled and you will only have a handful of sheet to pull in. Unlike the port approach where you had a ton of sheet to pull in.
In my seminars we call the starboard approach drill the "Slam Dunk Slant."

BY the way, this is all covered in my video on Mark Roundings, and the other video on Downwind Sailing. If interested we also have them in PAL version, on our website store.
Catsailor's Online Marine Store Good luck,
Rick