Like the look of the deck, I absolutely love proliferate. I have an older version of a deck up that needs to be updated on here, but it relies heavily on blue to proliferate instead of just the clasps and engines. There are thrummingbirds, tez's gambits...a lot to work with. Seeing just the engines and clasps makes me worry that this might be too slow. I might suggest trying to find room for some everflowing chalices or unwinding clocks - the chalices can give insane ramping and just scream destroy me in a deck like this to help keep your engines/clasps/cannons around, and with the clock untapping mana myrs and your proliferator ever turn you can effectively double your speed. Ooh, another NPH addition that might be awesome in here is hex parasite. Use it to clean up your side after a carnifex/zenith bomb. One of my favorites is paying the black, then tapping a chalice and eating all but a counter or two with its own mana. Swinging for 8+ is always fun, even moreso when its effectively off of 2 mana. I'll fix up my list and post a link...that early incarnation is nothing like what it is now so I would be a bit ashamed of it.
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I have something vaguely similar going in a deck I posted if youre interested. I tried to work in black, but don't have enough oh hand to make it worthwhile. Instead I just way heavy on the Tezzeret-iferate side of things. I rock steel overseers and they make early inkmoths absolutely brutal. They are my only infect and I still win by poison more often than not.
The nexus is great, but indeed pricey, and you have enough infect you probably dont need it. When I have one of those and a steel overseer to give it counters things can get nasty real quick. I dont think proliferate is tournament-quality yet because its relatively slow, but for casual games its great fun.
I've got a fun proliferate deck going too, and my only real suggestion would maybe be Throne of Geth instead of the decimator web. That way if your critters run out of steam later on you can still turn them into poison, assuming that first one made it through. Would throning a prowler let you proliferate twice? You could drop one chalice for another necropede or core prowler? I found that 4 can be too many early on sometimes, and also basically a dead draw later once you already have two going. If you can get them, inkmoth nexus is great in this kind of thing. They are the only infect in my proliferate deck, but they win it for me almost as much as my suddenly beefy army. If you want to slim it to 60, maybe drop the silver myr and the urns? Bountiful life might be totally useless against other infect. Just my two cents if I were running with that, if I went more infect-heavy with mine it would probably be pretty close.
I might switch the Contagion Engines for the Clasps, at least until you see that your opponent is going to try and flood you with critters. With one of those and a thrummingbird you can easily get Tez up to being an immediate threat as soon as he hits the field, and I would love to portal a clasp to get repeatable -1 counter drops and cheap artifacts to let Tez hit even harder. I also kind of feel like Hellkite and Mindslaver and Wurmcoil are nice alternative power hitters, but if it were my deck I'd try and either narrow it down, or drop it to one of each and more portals. That way you can Treasure Mage to search for which one is best for the moment, and odds are be able to portal it for as many as you need. I might need to pick up some portals and see how hard it would be to get myself into an infinite Mindslaver loop...10 colorless mana is not hard at all with proliferating chalices. Any comments for my own artifact deck would be much appreciated
I'm working on something similar, though more proliferation based. It's my only deck up if you want to check it out. I feel like your deck would be even more vulnerable to early critter removal, leaving you wide open to get smacked around. I dunno if you need the myr, though I guess they would help get you to your Jace's Ingenuity faster (I might Foresee instead). 4 Chalices might be overkill, I run 3 and sometimes seeing that second one isnt as useful as another blocker would be. I'm also uneasy about the accorder's shields. Sure an extra 3 toughness is good, but you'll never be using that vigilance to any real effect. Spidersilk net would help stop the fliers who might get around the thopters, or basilisk collar to make sure if you're losing a guy so are they. And I feel like Tez is only overdone because he can be way brutal. Dont have a ton of artifacts out? Turn the ones you do into 5/5s. But I've put him down with 6 artifacts on the board, used his search, and then dropped 4 my next turn and few things are as satisfying as a nearly unstoppable -20/+20 swing.
I've thought about a few other directions, more black for duress/creature removal or a splash of infect to keep their creatures down. Or some of the white metalcraft. Or some counterspells, especially to protect Tez when he first comes out, or to stop mass removal. I've had a few games where I could wait until my proliferate base was established enough to drop Tez, get an extra 2 counters on him and ultimate for 12-18 damage before I even attack. Probably not truly competitive, but I've been able to do 20+ damage on turn seven more than a few times now. Suggestions would be really appreciated, I just got going with Magic again about a month ago and I would love to make a splash at some events near me with something like this.