IGZ is an alternative to Hamachi, Leaf, and similar programs.

This is putting it mildly; it's nonsense. As a rule, there's a passage through an adjacent secondary resource or an unpaved road through 1-2 guard posts near the resource spawn, which means it can be easily cleared in the first week.

That's true, but if everything generates normally, there usually aren't enough days to reach the opponent.
The same principle applies to the rest period based on meeting. That is, if everything generates well, it won't be possible to intentionally arrange such a rest period, but if the generation is poor, you will meet before day 116.
Ultimately, it's much better to make a rule for a rest period based on meeting up to day 116 (these matches are incomplete anyway), but play those days simultaneously!