I’m not worried about the extra weight really its just a thought process at the moment really.

I’ve run tubeless in the past on Mavic XM719’s with Highrollers with success but am currently on tubes as i have changed the tyres over a few times recently. I’m still swapping tyres every so often and so don’t want the faff of converting to tubeless but am thinking of putting the Stans juice in the inner tube.

Will it still seal small punctures as it would if i was tubeless ?

Yes , but not as effective as it would be on tubeless tyres. you will also be bolloxed with a pinch flat then … where as tubeless eliminates that.