In actual practice you will find it easier to quickly perceive any deviation (drifting) toward the left or right edge of the runway if you positon the aircraft so that the runway centerline goes right under your seat. So that you are essentially "sitting on" the centerline. This makes the runway centerline appear to project perfectly forward in your vision, issueing out from behind the instrument panel from a point directly above the center of your control yoke, without "leaning" left or right. Any slight "lean" in the centerline to either side means you have drifted slight left or right of this ideal position. (A photo or illustration would really help here.) You'll be to see this immediately, and make a correction to come back to your original position, as far as left/ right drift goes.
In an airplane with side-by-side seating, this method does not put the nosewheel exactly on the centerline, but that's ok. There's rarely any reason to put the nosewheel exactly on the centerline, and this method allows you to perceive any lateral drift sooner than if the nosewheel were on the centerline, because of the way it allows the centerline to project perfectly straight forward in your visual field as long as you are maintaining the target picture.
It's like the difference between sighting a gun by holding it directly in front of you, versus sighting a gun by holding it several feet off to one side of you. The latter is analogous to the sight picture you get in a side-by side airplane when trying to take-off or land with the nosewheel, rather than the center of your own seat, aligned with the runway centerline. Unless the runway is incredibly narrow, the tradeoff in terms of increased obstacle clearance at the wingtips is not worth the greater difficulty in recognizing that you are drifting further to one side or the other, or that you are not actually aimed perfectly parallel to the runway heading. Both of those things are bad for the landing gear, whereas having the nosewheel two feet to one side is not bad for the landing gear.
To get a hands-on feel for how useful the effect I'm talking about is, sometime when you are driving down a long straight road with no other cars around, move your car over so you are driving with the highway centerline passing right under your seat-- as if you are "straddling" the centerline between your legs. If the road is very long and straight, you'll get the sight picture I'm describing here, and any slight deviation from this position will be immediately apparently. It will be much easier to maintain this position very precisely to a tolerance of just a few inches, than it is in the usual driving position.
At the very least, don't move on to try landing or taking off with the nosewheel right on the centerline, until you have completely mastered the simpler method described in this answer.
Try this: while taxiing down a long straight taxiway, position the aircraft so that the taxiway centerline goes right under your seat and projects forward in a perfectly straight line, and make sure you are sitting up perfectly straight, directly behind the middle of the control yoke, and memorize the exact point on the front of the cowl where the centerline disappears from view behind the cowl. That's your "sweet spot" or "gunsight point" -- remember it for later. (It's much closer to the edge of the cowling-- much further from the center of the cowling-- than you may expect.) When you are lining up on final approach, you can determine whether the aircraft is left or right of the runway centerline by looking at whether the runway centerline is "leaning" slightly to either side, and you can detect any left or right "drift" by looking for the first slight hint of any "lean" starting to develop in the appearance of the runway centerline, and you can tell whether the aircraft heading is exactly the same as the runway heading by seeing that the (non-leaning) runway centerline disappears behind the cowl exactly at the "gunsight" point described above, and not at some other spot a few inches off to either side. Note that you must actually be in motion on the taxiway when you pick the "sweet spot" or "gunsight point". Otherwise, even if the runway centerline is passing directly under your seat, the aircraft could be pointed a few degrees off from the actual runway heading, and it might be hard for you to detect that. When you are in motion, it is obvious-- if the wheels are firmly on the ground, and the centerline is staying under your seat, then the aircraft must be pointing exactly parallel to the taxiway centerline.
Naturally, on final approach, this cowling "gunsight" tip only applies when there is no crosswind or when you using the wing-down method rather than the crabbing method to correct for crosswind. If you are crabbing, the centerline will disappear under the cowling at some other point. But looking for the appearance of any "lean" in the runway centerline always will tell you whether you are on the centerline or not, and as long as you are trying to land with your seat rather than the nosewheel on the centerline, it will work just as well during the actual flare and touchdown as it worked when you were still a mile away on final approach.
PS-- if you a pilot with left-seat experience just learning to fly from the right seat, and you find yourself tending to land with the nose cocked off to the left, pay attention to the "gunsight spot" on the cowling the next time you are taxiing down a long straight taxiway (or while you are in motion on the runway). You may that your landings suddenly improve.