Converting 3-position cable choke to a variable pull knob

So my old FJ needs a solid 10 minutes of riding before it'll idle correctly - every morning I start it with full choke, and after about 10 seconds the choke automatically clicks down to 50% choke, which is not quite enough to keep the engine from dying. I usually just ride away at that point and hold the throttle while I'm stopped, until the engine is warmed up. I can micro-adjust the choke by manually pulling on the rod thingie on the side of the bike, but there's no way I can ride while holding the choke that way. I wish I could have a variable choke instead of the 100%/50%/no choke setup.

Can I just get rid of the cable and somehow install a pull knob on the end of the rod thingie?

Carbs are a foursome of Mikuni BS 32's if that's any help.

Halp?

At first I thought you were describing some kind of futuristic automatic choke, haha.

Might be easier to take apart your choke lever and see why it's slipping, could need a new plastic ring or something. In theory you could convert it to a knob-style choke... YMMV, I don't have an ounce of craftiness in me for stuff like that.

It seems to be clicking down to half-choke by design... it does so once the engine reaches ~4-4.5k RPM under full choke. But yeah, maybe it's not supposed to do that. I don't know these things.

Now that I think of it, the current lever is what's preventing a smooth/linear choke operation. I guess I could mount some type of universal, variable choke lever somewhere else on the clip-ons.

Something like this? http://www.dimecitycycles.com/universal-choke-lever-78-handlebars.html

Any bike shop will have a EMGO catalogue with two pages of different choke knobs like the one in your link.