What Alejandro said, plus the following.
All these are quotes from this thread:
O Sensei developed his art over 60 years of intensive training, the techniques (core techniques including koshi nage) are based on his experience, more precisely the techniques are
his distilled experience. When people modify a technique claiming their own "understanding", I wander how it compares to Founder's (being extra polite here
Oh, and also this: there is
a right way and there is
a wrong way to do things, and while its true that there may be more then one right way, that does not mean that every way is OK.
Where to begin........... In terms of mechanics, to some degree, yes techniques all boil down to inherit motion(s) that render them as being true to a form. So for example ikkyo, regardless of aikido style, would be recognizable as ikkyo though the name might be different. But here lies the catch, when preforming technique, the circumstances are never the same, be it ma ai, different ukes(in regards to height sizes, aggressiveness etc) and a host of other circumstances, generally means you can't do the technique the same way every time. Even in Ikkyo, some styles say step in immediately or other say cut down the step in, other say take the ikkyo offline the line and away, other say cut down in arc, yadda yaddda yadda. So the point, yes techniques have a universal form to some extent, but its the application/execution/situation that renders degrees of efficiency. All the ways of doing Ikkyo have merit, but how you apply them,being the various ways, yields degrees of efficiency. But there is no magical cookie cutter way/technique that works on everyone can every single time. There is form, then degrees of efficiency of the application of said form. You want the so called "right way" save it for testing where you have to do it a certain way to be graded on with semi complaint ukes who don't want you to look bad during testing and predetermined attacks and responses.
Back to the thread topic, go ahead and use the wide stance. There wont be this great schism in aikido like there was in between catholic and orthodox churches over this. There will just be people who will walk with a limp and those walk away from throwing koshinage without a limp. Probably like 99 times you throw with the wide stance, you will be safe; its that last 1% that will get you. Not saying anyone is right or wrong, (though personally wise stance looks sloppy to me) its more of matter of safety.