Second, a Volquartsen sear found here with free shipping: Rimfire Sports & Custom: Volquartsen Ruger Mark II / III & 22/45 Target Sear
No need to buy the whole Volquartsen kit if you have a 22/45 you guys. Its a waste of money. You only need the sear, and trigger if you want it. Everything else doesn't work or isn't needed for 22/45's. The hammer you have in your gun performs just as well as the VQ one.
Do those two things and you'll have a 2lb trigger pull that is just out of this world. Add a VQ trigger for pre and over travel screw settings if you want and you're good to go.
Just an update since it's been about a year since I posted this.
The kit from VC was way too much. That's nearing what I paid for the gun and there are other upgrades I'd rather get before that. I ended up getting a couple of the bushings from Tandemkross since I have a MkIII and a 22/45. I also got a speed strip kit I'm going to try on one that's supposed to make it easier to field strip for cleaning. The tools that I needed just showed up yesterday to do it all.
Hopfully I have some time I can do it today. Also, that video from Tandemkross was VERY helpful. I was worried that installing this kit would be harder than it looks.