UKC

I’ve watched a few videos of people using a gri gri to rap down and work a section of a boulder problem whilst alone. 
 

Anyone help me out, wondering whether that’s possible using an ATC and what would be the “right” way to do that? 
 

It would be a big faff. Get a gri gri or don't bother. 

I've been wondering the same thing, but I never fancied risking it. Something like this with a stop knot tied in the trailing rope?
youtube.com/watch?v=pSkhzMDCKz8&

It seems a lot more risk and faff than ordering a gri gri!

how big is the boulder?

why don't you just get a gri-gri or borrow one off a mate?

Most people wouldn't be trying sequences purely on a gri-gri as you can't take in the slack on hard climbing and if you can, you don't need to be practicing it. It's more for checking positions and sussing out single moves and holds etc.