"That tall Klingon is beautiful."
Translation:'IH tlhInganvetlh woch.
It is the exact same as the difference between "big" and "tall" in English. Something can be big in ways that aren't necessarily tall. And if something is tall, but narrow, you might not necessarily call it "big", although sometimes the tallness is sufficient to still call it "big". There are lots of situations where either or both words are appropriate, but they still have slightly different meanings and are not really interchangable. tIn means "big" and woch means "tall".
Does " 'IH tlhIngan wochvetlh" mean the same as " 'IH tlhInganvetlh woch" ?
No. It's simply wrong to put a noun suffix of types 1–4 on a verb like that.
The only noun suffixes that can (and have to) go on a following adjective-like verb are the type-5 (syntactical) ones such as -vaD "for" or -mo' "because of".