Create Using the OSR Rules 'You Know" and Your Audience Will Find You
Over in The Tavern's Facebook Community, a discussion asking about the size of the Swords & Wizardry Community and whether it was a viable community to create for, slid in the direction of system preference (or more exactly in this case, system dislike)
Here's how I see it - all things being equal (size and activity of the various gaming communities, commitment of the publisher to support the material and the communities' support of the systems in question) write for the OSR system you know the best.
Not that surprising, it it?
Obviously for me that means writing my material for Swords & Wizardry Light and Complete. For +Pete Spahn that would likely be Labyrinth Lord. For +joseph browning it would likely be OSRIC. For +Chris Gonnerman it would be likely be Basic Fantasy RPG. +James SpahnS&W White Box or White Star. The list goes on.
The truth is, any DM worth their salt is going to convert adventures from one OSR system to the ruleset of their choice, with little difficulty and often on the fly, just was many of us used Basic and Expert adventures in AD&D back in the day and I do with DCC RPG Adventures to Swords & Wizardry today.
Some will say writing for the "hot" system of the day can help sales and I'm sure it did with White Star and third party publishers. I'm just not so sure that system loyalty is a driving point among the majority of the OSR community.
The question then becomes, is there an OSR system that is a sort of Rosetta Stone between the various clones. I'd suggest Swords & Wizardry Core for this, but it's more about the ascending / descending AC and perhaps single save than in being "Swords & Wizardry". Adventures written for S&W don't need an AC adjustment to be used with the other clones or original systems, but in truth, you could write an adventure for ANY clone and include ascending and descending AC in the stats and be 100% compatible with every OSR system.
There is a reason that the OSR graphic is popular to place on OSR products - its the OSR damn it!
The Minotaur for Old-School Essentials
*Requirements:* Minimum STR 9, Minimum CON 9
*Prime Requisite:* STR and CON
*Hit Dice:* 1d10
*Maximum Level:* 8
*Armor:* Leather, including shield...