I'm skeptical of Strat's ILI description, in part because it says that ILIs have a gift of always being on time.
But apart form that, both ILIs and IEIs have a tendency to accumulate information. IEI's tendency to research and read a lot has been commented on a bit.

Determining whether Ti is the 6th or 8th function is a little difficult because strength is relative. It would be a mistake for someone to say you have weak Ti just because they disagree with you or think you're in error. A "strong" function doesn't necessarily mean one is competent. A "weak" function doesn't necessarily mean one is incompetent. However, one is theoretically more competent in one's strong functions than in one's weak ones.

Here are some behaviors in full-fledged IEI types I've seen that may suggest HA Ti:
* Enjoying "deep" conversations with a T person or leading a discussion with a T person into philosophical territory but relying on the other person to develop and organize the concepts or supply the logic.
* Reading a lot of books on science but avoiding the really mathematical stuff.
* Focusing on less technical areas of intellectual interest
* Accepting new theories and schools of thought uncritically
* Accepting weak theories on the same footing as stronger theories
* A tendency not to innovate in the technical area but rather to accept the standard views "as is"
* Become a devoted follower of other people's Ti

On the other hand, there seems to be a border area; some people who are IEI may have very strong technical skills, for example.