General

About 300k if you use B-Step.

Just tested. Took 300k for bstep. 1hit with phase dash sometimes with 850k, 1hit 100% off the time with 900k.

300k range with bstep
800k range with phase dash
6m with mesos explosion

Fastest would be to use meso explosion while there's mesos. Otherwise phase dash from end to end until you can hit the end of the map with boomerang stab, and then canceling the animation and phase dash the other way. If you can't one hit with mesos explosion, then just don't use that. If you can't one hit with phase dash, then probably the sequence would be to boomerang step + phase dash to cancel animation.

250-500k unbuffed

[url=http://www.basilmarket.com/PC-New-Mapler-Guide-Wiki-234]Give this a quick read.[/url] I'd say if you can 1 hit with phase dash, it'd be a pretty good skill to use. You can also ME if you'd like.

No idea about Shadowers, but I 2hit monsters in sdh at 202 with about 170k range buffed, I am 2hitting them for a while so maybe even less range, this is only for NL tho, hope it still helps.

For shadower a using bstep, 300-350k range. Using phase dash, it's like 700kish. If I remember correctly. It's been a long time since I didn't 1hit.

*edit* I'll take off gear tomorrow and get an exact answer for you.

I don't know very much about Shadowers specifically...but a good number to aim for if you plan to get involved with training, etc is around 400k - 700k buffed.

Here's a guide I wrote that tries to cover at some length every aspect of gearing from beginning to pro.
It's long and boring. It's mainly to be used akin to an encyclopedia where you just look for what you're trying to find out more about. It's not written with beginning to end reading in mind.

http://www.basilmarket.com/MapleStory-ashleyattacked-Story-23731.html

^ Link to my guide is working now.

If you're looking for help with bossing for any specific reason...if you can find me when I'm not afk in game I'd have np helping you out with whatever I have time for.