When I use grapeseed oil in soap it's usually a smaller percentage, but I don't use it much in bar soap.
Like KristaY, I also did an experiment with different oils, but it wasn't a DOS experiment (even though some did develop DOS). It was a single oil soap experiment. I used only one oil in something like 16 different soaps. My goal was to see what each oil was like as a single oil soap; how it performed alone; if I would like it; how it lasted, etc.
Looking back at my notes, here's my experience with 100% grapeseed oil soap: Took a long time to come to trace; had to heat it up (in a warm water bath) to get it to trace with a stick blender; very soft at 24 hrs, 48 hrs, and still 'pretty soft' at 72 hours. And it was 'very white'. Then for some reason, the notes on the grapeseed soap disappear! Bummer, impressions are lost as I didn't record them and of course I do not remember now! I do know that it apparently did not impress me as a single oil soap, or I would have written that down. But I didn't write that I hated it either. So I am sad about that. Perhaps I need to repeat the experiment now that I have more experience and a better grasp on what I am doing! And what happened to that soap? Well I still have some that survived without any DOS and that I do test when I think of it, but it is not among them. It must be one of the DOS-developers* from that group that I threw away one day, but forgot to write that one down.
Anyway, I do occasionally use it in a soap recipe because I don't want the oil I have to go bad just sitting around in the bottle. I prefer to use it in a bug repellent spray that I make, which is why I bought it in the first place. But when I use it in soap it is usually just for mixing colorants so the percentage of the recipe is very low. Oh, and it is also in a recipe for a LS I use for a woman's shaving soap that I absolutely love. So I do have a use for it outside of solid bar soap. And now I use ROE and EDTA to address the DOS issue.
* OK, who here remembers working with DOS on their pre-historic computers (with tiny little memories) and had a chuckle at 'DOS developers'? I sure do and did.