OK, here's how I did my delete. This is on my rallycross FX16 which already has other emissions deleted. For a while I was running a canister delete just by capping the vent line in the engine bay. It works, however since the system is sealed and the gas cap is a one way safety vented cap, it'll puke gasoline back up out the cap when things warm up enough. Modern gas caps are designed to let air/pressure in, but not out until it reaches a critical pressure where it then safety vents. I'd read other solutions of finding old gas cap which isn't sealed, or drilling a small hole in cap. I wasn't thrilled with that idea.

And then I saw someone post about this vent valve that Fuel Safe sells. Part number TPV8, it's a vent valve designed pretty much just for this. At static pressure it is closed. Under light vacuum it opens, thus letting air in so the fuel pump can work properly. Under positive pressure it's closed until it reaches a point like the gas cap, but the pressure is much lower, only around .8 psi, so it allows much free-er venting.
And as a further safety measure which might be overkill, I installed this other vent valve. A rollover protection valve which installed upright is open and allows venting, but has a ball bearing valve that once it's beyond horizontal slides over and closes the valve, thus preventing escape of liquid gasoline should you find yourself upside down. I sure don't plan on that, I don't have a roll cage, but if it ever did happen, it's one less thing to worry about!
So here's the two valves clamped onto the old charcoal canister bracket, plumbed with 1/4" fuel hose, and a K&N vent filter. The 1/4" is a tight fit on the TPV8 since it's 8mm fittings, but the other fittings are 7mm and fits perfectly.
Road tested yesterday with no problems and no fuel spillage. True test will be next week at race where car will be sitting out in sun all day!

You do realize what the purpose of a charcoal canister is right? It captures hydrocarbons as they are venting. A gas cap does not vent, the purge solenoid allows the pressure to alleviate into the charcoal canister, and then into the intake. The charcoal canister captures the hydrocarbons that would be released into the atmosphere, allowing clean air to recirc into the intake and be burned in the engine. That little K&N filter won't capture those hydrocarbons. You are just venting fuel vapor into the atmosphere.

That pressure builds up when the fuel starts evaporating.

Granted, I deleted my charcoal canister, but I didn't even bother with the valve, because I drive my car every day, and am not really concerned with teh evap emissions.

You did a much better charcoal canister delete than I did, but I figured I'd shed a little more light on how the evap emissions system works.

Yes, I would not recommend deleting the canister on a daily driver. There is no advantage in driveability or gain any power unless there is something wrong with the system, namely a vacuum leak somewhere. You'll might actually lose a tiny bit of mileage since the canister absorbs fuel fumes, and then releases it back into the intake to be burned instead of floating off into the atmosphere. What it gained me was losing a little weight and simplyfing the engine compartment by eliminating a bunch of vacuum lines.
The K&N is to keep any potential dirt from getting back into the tank through the vent line. Some people just leave the vent line open, or put the little K&N on it. I liked the idea of the valve I put in because it's still sealed when at rest in the garage so you don't smell fumes in garage. When I took it to events and it sits out in sun and after a couple runs and things heat up, the gas cap would vent making strong fume smell and liquid gasoline dribbling down the side of the car. We shall see if I get any at next event with this setup. I didn't get any through my day of test driving.

OK! Report after event, works like a charm! No fuel pukeup, no strong gas fumes, engine ran great for once. Heard weird soft honking sound once, I think it was the valve popping off. Hey, it's my blowoff valve!
Now I just have to work on my driving, got some pretty fast times, but consistency bad so I placed low since rally-x is cumulative time, not best time.