Agree with your post.
The reason that OSR does not generally need seeding is that pure OSR honey sets finely and so is an excellent seed in its own right. Sometimes OSR comes in with dandelion, though, which granulates coarsely, and you can end up with fine set OSR littered with 'sugar crystals' of coarse dandelion honey granulated. Do not use this blend as seed.
There are two processes -
1) seeding to improve/control crystallisation texture - i.e. grittiness;
2) 'creaming' to reduce a solid set honey to a paste - i.e. spreadability
It can be an either/or situation, not automatically both as in the case of a honey with fine texture already.
For seeding you need to liquefy and cool the 'gritty' honey, warm the set seed enough that it is pliable but not enough that liquid honey appears around the edges. 30-40 seconds or so in the microwave per 1lb jar (lid on) should do it. Spoon it out and stir it in like a big milky swirl in the liquid honey. We use a paddle mixer in 30lb buckets for speed. Put somewhere cool and allow to set solid. If you bottle it before it sets it will usually have a fine texture but be rock solid in the jar. You've adjusted the grittiness but not the spreadability.
For creaming you need to warm the solid set honey gently but enough to make it pliable, but not so much that there is runny honey around the edges - this leads to frosting in the jars. Once pliable, cut with a pallette knife (or similar) then mash vigorously - we use a giant potato masher from a catering supplier. You're aiming for a fluid paste with no big lumps. Bottle whilst still pliable, and you will end up with a soft set honey in the jar that will firm up a little but stay as a spoonable, spreadable paste. Unless you previously seeded it then it will be a paste of whatever coarseness this honey naturally adopts. You've adjusted the spreadability but not the grittiness..
Taking both processes together allows control* over both grittiness and spreadability.
We've just gone through this process with a few buckets of ivy honey, makes a lovely caramel-coloured paste with a 'robust' flavour...
Dan.
* in as much as anything in beekeeping can be controlled by the beekeeper