Kleese’s level 4 left helix option reads:
“Energy Rifts will now link to each other when near each other. Their output will be increased times the number of rifts in the network.”
After extensive testing, it seems a rift only checks for this effect once: how many rifts are in link-range when it is first built. That means only the third rift in a 3-way network will be at 3x output. To get a network of 3 rifts to each benefit from this helix, you must place 5 rifts total, the 4th & 5th placement replacing the 1st and 2nd rifts placed. Similarly, with the +1 Rifts Allowed later helix upgrade, a 4 rift network will take 7 rift placements to get the full benefit… Further, if you get a rift up to a 3x or 4x multiplier due to the network, but then relocate all the older rifts elsewhere, it will remain at its elevated output even though it is no longer in a network.
A second issue is that rifts only count direct links to other rifts, contrary to the text stating it depends on “the number of rifts in the network”. A network formed by 3 rifts in a row i.e.: X----X----X, even after multiple placements to update them, will only have 3x output for the center rift, the outer two rifts will only be at 2x output as they only see one direct link each. Only a triangular arrangement (2 links coming out of each rift) can get all three rifts to the 3x expected for a 3 rift network.
Presently, I have generally found it to be more time & space-effective while playing as Kleese to use rifts as short-lived offensive tools, as a defensive network must be a small, concentrated clump to reach the expected output (and thus any supported teammates must be corralled into an exceptionally smaller area), and it takes nearly double the expected time to truly complete the network (5/3rds or 7/4ts the expected time depending whether they have access to a 4th rift).
All my tests were done in solo in story mode where I can carefully control the variables. Rift output-per-pulse was measured by shield replenishment.