I've got the tall upright ones on my trailer, like KY has. My trailer came with them, they work well. Obviously Lee's would be even better because the boat can't move sideways at all. I have seen trailers with two tall uprights, one at the very rear like mine and one on front of the guards. I have a second set but as my set up works I never bothered to fit them on.
I use the same slides as Lee has as well, the trailer acts almost like having rollers, I first used them on a trailer about 13 years ago and I'll never go back to carpet or rollers. I don't undo the safety chain or winch strap until I back the trailer in the water, the boat will slide off on to the concrete.
I have my boat sitting as low as possible on the trailer, the centre of gravity is lower, better on the road and the trailer doesn't have to be as far in the water .
I drive on the the winch post but I have it reinforced, I don't trust the factory set up, looks very flimsy to me. In an accident the boat will end up in the Landcruiser cabin. Depending on the ramp I use as to how far in the trailer goes, in any case the rear wheels of the LC are 3'-6' away from the water.
I always trim the motor up, lifts the bow, saves my prop getting gravel rash and saves the boat ramp too.
As you can see in the photo, I don't store the spare on the trailer, I put it on when I go away, I don't even bother when I go to my local ramp. Saves the tyre from the sun and saves weight too.