This is my current pass at a punishingly taxing NEH deck. A couple of key thoughts:
1) Grail ice is incredibly punishing and taxing for very small investments Even at the top end you're paying 6 credits for a strength 4, 3 subroutine code gate, and most of the time you're rezzing Galahad or Lancelot instead, which is even cheaper for similar levels of tax. (Basically, Grail ice tax on the strength of their subroutine count, and there aren't very many efficient ways to make "more efficient" runs against multiple subroutines.)
2) This deck, obviously, plays wide. You're going to be installing one or two new servers a turn on most turns, and most of them are going to be unprotected. Normally this opens you up to having to come up with solutions to run-efficiency boosters like Desperado, Security Testing, and John Massanori, or it leaves you vulnerable to the occasional Whizzard match-up. Which brings us to...
3) Manhunt is something of an all-star in the deck. Yes, it's quite an expensive current to be playing, but it adds a real tax to each run the runner makes. If they're playing Gabe with a Security Testing and Desperado, you get to tax that first run by 2 credits, negating the Security Testing. Turning that off is amazing. Similarly, Whizzard pays the equivalent of 2 additional credits to trash things, almost blanking his ability. This gets worse for the runner once you get one of the Primary Transmission Dishes rezzed, you can pretty much guarantee that the runner will have to take a tag any turn they run, which they'll have to then spend a click and 2 credits getting rid of. Eventually, even the most efficient runner stops trying to deal with your constant server spam, and you can probably sneak out an agenda, or just sit back and rake in the drip economy.
4) In the unlikely event that the runner goes tag-me (in all my testing I've never seen it happen), Information Overload is there to maximize punishment. It's possible that playing two of the things is over-kill, and that one should be a Closed Accounts or a Universal Connectivity Fee, just to vary things up. So if you're looking for some minor places to experiment, that's where I'd start.