Hi,
DXF is the general across the board CAD file exchange format. If you want to make it available to as many as possible, then most CAD programs can open these.
If its just so people can print off and build, then draw in whatever program you are happy with and generate a set of pdf's directly. (You may have to scale them down to A3 size) and people can then plot them at whatever size they want at their local print shop.
There are free pdf readers available on the net, and also various free pdf generating programs, besides Adobe.
PDF is the standard way now of sharing files and still keeping ownership of the original data. People can print, but not alter or reuse in another program, even rotate 3D images.
This is how we do it at work, and how I distribute my own drawings.
Have attached an example of an A1 size drawing generated as an A3 (half size) PDF and can be printed at whatever scale is required.
Hope this helps.
Have followed your EeZeBILT thread, and web-site with much interest, and will send you a scan of the back cover off Model Boats December 1974, which is the KeilKraft EezeBILT advert, as soon as I can get my scanner back into operation.
cheers
vnkiwi