It does make a difference from the perspective of ease of putting in the reef under sail. Personally, when I sail, I typically make a decision before I go out whether or not to reef. It is easy enough to let out a reef solo, if conditions lighten, but more challenging to put one in when conditions get rough.
Roger, an experienced sailor and a marine architect, said the topping lift is the "key to easy reefing." He didn't say why though! My thought is that is that, when you reef (especially under sail) you must release the main halyard to drop the sail enough so you can hook the forward cringle on the reef horn and adjust the reefing line pulling down the aft cringle. When you do this, an adjustable topping lift can be used to hold the boom up, which makes the operation safer and more controlled as the main halyard doesn't have the weight of the boom pulling down on it. After all the lines are secure you can then tension the main halyard again and release the tension on the topping lift.
I really hadn't put any thought into it before, but now I am thinking that I am perhaps better off making my topping lift adjustable by sacraficing or otherwise adapting (I like that idea better) my second reefing line for use as an adjustable topping lift.
Why didn't the professionals who designed the S2 make the topping lift adjustable in the first place? As you are no doubt learning, there are many ways to rig a sailboat. There are also many places to sail a sailboat. It depends what is important to you and your area. Somebody in San Francisco Bay might put a reef or two in frequently, due to what I understand are very windy conditions there. In Boston reefing has been strictly a mental exercise for me because, frankly, winds are often light in summer and I can pick my weather to go out in. However, if you plan on cruising you should think about your reefing capabilities because weather can change quickly and you should be prepared for any eventuality, including an engine failure in bad weather.
Roger pointed me to a story he has on his site. He was solo, motoring his boat to the yard for winter storage and his engine quit. See the link.
http://home.roadrunner.com/~rlma/Strider.htm#Last
Now nobody
intends to end up in such a position. However, read the story and then imagine that it is you, that you had furled your jib up, are still overpowered, but need the jib to tack effectively. Assume you are now mentally and perhaps physically tired from the stress and strain of the situation and need to put a reef in the main (he apparently had one in and put a second in). Now the decision you made last fall on whether or not to make your topping lift adjustable comes back to haunt you...
Now there are a
host of things you can install or do on your boat to help in different situations. Think about what your plans are for the boat, make a list and get to work. It may be more important to replace some running rigging and do some engine and other maintenance than to worry about reconfiguring things. The topping lift modification has just made my "to do" list, but it won't stop me from sailing and it isn't on the top of the list. I have to reseal some chain plates first to protect my investment (just mailed in another payment yesterday).