The OS 40LA does use an A3 glow plug. Really should have at least one spare on hand at all times...they're not very expensive. If you question the plug's integrity, just install a new one.

I can't remember exactly for the 40LA but I believe the manual recommends an initial opening of 1 1/2 turns for the needle valve from full closed. If there is no reference point for this setting, just make a small dot on the top of the valve with a Sharpie so you know how much you've opened it. I don't still have the Internet link for OS but it's really easy to find. Search thru something like Google for OS and they have online manuals/operating instructions for all their engines. Just be careful at the first not to run the engine too lean. Their manual has recommended tuning guidelines.