Archee ; Why would you want to train with an OML if at the completion of training there is no likelihood of employment ?
An OML gives you authority to exercise the privilage of your Commercial licence in a Multi Crew Environment ONLY.
At the initial hiring stage, most emploers will insist upn a full, unrestricted class one. They accept deterioration thereafter, to a degree. Hiring someone already disadvantaged and likely to detriorate further is asking too much of most employers Insurers.
Looks like the top Pro Training institutions out there advise this already and some, as you say, do not even accept for TRaining unless you have a Class one.
Watch out for the rotters who will just grab your dosh anyway.