Could you check this over

Very well. May I quote you when I make the post (as I have no idea how to link here)? Also, with this information and given that De Vaan (for some strange reason) has *wh₁itis, could we maybe maybe posit *wéh₁ytis and propose that some of the forms came from the oblique form? This would give:

• *wéh₁ytis:

  féith (*wēitis)

• *wh₁itéy-:

  *wiþiz

  výtis

  vītis

I'd also like to add the wrinkle that, if we assume that वेमन् (veman, “loom, slay”) and vīmen stem from the same form, this points towards *wéymn̥.
PS: Is there a particular Vedic dictionary that gives word accentuation or can you construct it from rules in Panini?

I don't know much about Sanskrit so I can't help you there.

I don't find *wh₁itéy- very convincing as the origin of the Balto-Slavic forms, personally. The long vowel can be explained, in general, as either from a following laryngeal or from the new length ablaut. However, such new long vowels were always used in specific derivational processes that were innovated within Balto-Slavic, and I find it very unlikely that an old formation like a ti-stem would have such a long vowel. What also needs to be considered is that ti-stems became productive as infinitives in Balto-Slavic, so if one of them happened to survive as a noun, it must be an archaism and thus can't be an innovated derivation at the same time.