Denny,
if you do a general search of all the forums, with the button at the top of the page, the system returns 178 hits, for the word "splitrim". It must be all one word. If you do a search for "splitrim danger", you will get 16 hits.
Your rims sound like the type that do not use a separate lockring. One part of the procedure not mentioned so far, was to air it up with a remote hose, with no valve insert, and after the assembly has seated at minimum pressure, let all the air out. This I believe is in the manual.
There are some alternate rims available. I bought some on Ebay from 80's trucks. Two are Dodge and one is a Ford rim. I usually search for "8 lug" on Ebay motors and I get about ten pages to review. What I then look for is a rim with a 6" width. They usually will have an acceptable setback.
There is also a white rim with spoke like formations that is aftermarket, and very ugly. I understand that they fit too.
By the way, my Ford rim has the letters "0923 87" and the Ford script on it. I have been told that this is not a Ford number so it is a mystery.
Fred