Dybo's law

I read on in the article so I could understand Dybo's law and get to
understand why some Russian verbs end-stress the 1sg and root-stress
other persons and numbers. This is what I found

*vezó:
*vezés^U
*vezétU
*vezémo
*vezéte
*vezó,tI

->

*vezó,
*vezes^Ú
*vezetÚ
*vezemó
*vezeté
*vezo,tÍ

etc

So this is where that alternating stress appears. All forms move the
stress out to their final vowel or jer, but 1st sg. doesn't have
one, so it can't.

But there is something I can't understand. Instead of moving stress,
the 1st sg. lets its vowel grow a tail! It self-nasalises! Is this
part of Dybo's plan?

Because if 1st sg.'s vowel didn't self-nasalise there must have been
a nasal ending which helped. And that must have been -mi or -mu,
with a vowel, since 2nd, 3rd sg and 3rd pl. also have primary-
looking endings with -i's and -u's (which have become jers). But
then we would have

vezómU
vezés^U
vezétU

->

vezomÚ
vezes^Ú
vezetÚ

and no stress-alternation?!


Someone please explain.



Torsten