All coleman lantern work best at full throttle, so expect some pulsing when turned down. There are frosted globes and metal shields available to 'De-tune' the lanterns some. Also tinted globes, yellow and red come to mind.
Sounds like you just had some old "varnish" in the 502, and it's dissolving and burning clean! A 502 stabilized very fast, of three I have here, one lights like a house stove, no issues, and blue flame from the start. If you throttle a 502 like Drew says, 1/8 turn on the knob, and throttle back on the cleaning needle to 50% until it comes up to full speed, then open the knob to full bore, and work the needle to max output. I'll also give 'er a stroke or three on the pump every 15 seconds during warm-up, keep a good head of pressure in the fount. Murph
What Murph said, give the pump on the Coleman 502 a few strokes while preheating the generator. A great stove. Buzz
Coleman made some smaller white gas lanterns that were sort of congruent with the Feather 400 series of stoves, quite a lot smaller than the "regular" coleman lanterns. My favorite has always been the M 200 single mantle as I've always been able to throttle it down so it wasn't as bright and loud, and a great deal easier on the eyes while playing cards on a picnic table at night. Hanging a lantern from a tree branch makes the light easier to use as well. If you really want a controllable lantern go for a single mantle Coleman Propane burner. They're available, you just have to keep looking. Gerry
I've never had a problem with the 400, and still have one I bought in the 80's back in the States. That, along with the matching Peak One Lantern, have always been the most reliable gear I've ever owned. I used them up until a few years ago when I moved the UK and have never considered upgrading or replacing them.