One thing I noticed - I did the body final coat and neck final coat at the same time and the neck has come out with no issues, in fact I did two necks and they have come out looking and feeling great. If I don't have luck with the body final coat, perhaps I'll try using the neck final coat before I resort to trying.. a certain popular oil product.
I think this may be because necks generally have finer grain, the larger the grain to the wood (e.g. Ash) the more troubles there seem to be with the DT top coat. This is one reason why I think inadequate grain filling is at least part of the problem (for me anyway).