I am looking into buying some heated grips but I would prefer some that are no bigger than the standard grips as I have quite small hands. Was looking at the datatool ones but they are quite large.
I think you'll find most of them are. I have a set of R&G heated grips which work well but they are bigger than standard grip size which suits me as I have large hands. I can see in your case with small hands it could be a problem.
I have Oxford premium Hot Grips on the 929- don’t seem that much bigger than standard grips, they also come in differing grip styles. The controllers intelligent, so need danger of being left on when the bikes not running without the need to fit a relay.
I had the oxford sports grips on my old Thundercat and to be honest they seemed huge compared to stock but in fairness I preferred that as I have big hands, think there's always a trade off in these instances. Have you considered Keis heated inner gloves as an alternative. I've got these now and I'm impressed with their effectiveness compared to grips which heat your inner hand but the outer, which takes the brunt of the cold doesn't get any benefits from the grips.
Oxford Hot Grips Sports are fairly close to the OEM grips size, but they're shite IMO. I find they barely heated my hands at all because my whole hand isn't on the grip (not even close to whole hand) and is also constantly touching cold metal levers. Mine mysteriously failed after a few months too (suspect water ingress to switch). Keis heated inner gloves however are brilliant and what I use now.
On a related note, I fitted rubber lever covers (from ebay, meant for BMX) over my brake and clutch levers for a while (not on my Blade though) and it actually made a difference, as for me, the levers contribute greatly to cold hands. Don't need them with the heated gloves though.
I had Oxford Premiums on my last bike and they were as near to standard size as i could find but as JM1 says, poor heating.
