Hello everyone,
For a couple of years now I've been working on the UDK engine. I've written a few tutorials, all kinda small in size. Now I'm thinking about the possibility of writing much longer and more advanced tutorials, but right now I'm unemployed so I thought I could do it all more in-depth and detailed, and make it commercial.
I know this sounds like UDK-related only but I posted on the UDK forums and my post was largely ignored for now. Either way, this involves writing tutorials and game development in general so I thought I'd post this here as well.
It'd all be based on UnrealScript content so the best format would be written and with images at the side. Making a video tutorial for this is out of the question.

About the topics - They'd be centered around game saving/loading, inventory and items. I'd start off with the basic Sapitu implementation (a UDK savegame system that's publicly available) and then my own extension of it, which are all needed for my own implementation of an inventory system.

The first question would be: is there enough public for this to be worth it? I know for a fact that at least a few people would be interested (I've been asked to write a tutorial about my inventory implementation), but I don't want to do such a big effort to reach only 4 or 5 guys with this.
So this is also a call to anyone that has ever created a tutorial, commercial or free (best if someone has created both!), or even a book, to throw here their experience with the results. is it worth it, based on the public reception? comment and rant away!

And the second question: what's the best medium for this? digital or printed book?
if digital, do I need to code my own website with a user authentication and payments system (that'd be overkill!), or is there some site where I can sell this kind of stuff? (I only know Eat3D in regards to commercial UDK tutorials, and it's not some sort of marketplace where anyone can sell. Turbosquid and similars aren't really suited for this either)
what about a printed book? I know only a few UDK-related books have been published and people have asked for more. Is this a possibility at all?

I'm trying to get all of this straight to decide if it'd be a good idea or not. As I said I'm unemployed (save for a small website-upgrade project I'm about to finish) so I need to invest my time wisely

Well, this doesn't belong in Breaking In. I don't think it belongs anywhere but in the Lounge, so that's where I'm moving it.

I think the number of people using UDK is pretty small? So, you'd be entering into a very vertical/niche market. Who knows though, maybe if you write a really good book/tutorial set a lot more people will use UDK?

If you go with a book, and everything works out perfectly, you'll have your product sitting on a retail shelf in a book store or available as a digital download on a service like Amazon. The good part about that is your book will have exposure to the "window shoppers". People may not be looking specifically for your book, but may pick it up if it sounds interesting or related to what they are doing. However, most books have to be published and printed. You'd have to find a publisher willing to publish your book and an editor who can proof your work. Publishers would naturally want a portion of the profits (10%? 90%?). But, if you have a publisher on board, they'll have an interest in getting your book done so you'll have a bit of pressure to actually deliver.

If you go with a website, you'll probably want to design your site to have a few free tutorials to get people started (and to vouch for the overall quality) and the rest are available behind a pay wall. You'll have to do all of the marketing for your site because that's the only way you're going to get traffic. A percentage of the traffic will convert to unpaid readers, and a percentage of those will translate into customers (instantly or over time). Once you've got your infrastructure and content setup, you'll make your money through traffic volume. Since you're in a vertical market with a limited pool of potential customers, a slim margin of traffic will translate to dollars. That's going to mean one thing: You have to give away more content for free and put your paywall farther down the line so that you can actually build a community of prospective customers before you hit them with the sales pitch. Since you're relying on traffic volume to make sales, you'll want to make your content as accessible as possible to the widest audience possible. Maybe the english speaking audience isn't going to be your money makers, but the chinese or indian or japanese, or german (etc) is where you hit paydirt?

Either way you go, it's going to require a substantial effort on your part. Work hard, work smart, and work persistently and you can make anything you put your mind to a success.