In essence, the upgrade is far too expensive to build for what you can do with it.
My proposal is to drastically reduce the e cost of the upgrade and increase maintenance cost to 10000.
The idea here is that the time you can cloak for will then scale according to E income and storage, making it useful around t3 stage as a hit and run tactic. Remember that overcharge costs E, so you will only be able to overcharge once, fall back, and wait for your e to refill.
As for the build cost, I was thinking somewhere in between aeon heavy shield and sera advanced nano, but still 6000 in mass.
Unfortunately I don't think showing this in a sandbox would really help. and have no replays. There is this gyle cast so analyse it as you wish: https://www.youtube.com/watch?v=WBcTSEzFQzs. If anybody can provide replay number we could see what timings here would be like with the change in order to figure out if it is viable or too easy to cheese with.