From the 8a.nu website, comes this advice:
"The ideal time to rest in between attempts varies between 1 (for one move boulders) to 90 minutes (after long endurance routes)..in general climbers should rest much longer than they are used to.
Adam Ondra usually rests up to one hour after being pumped and if you really opt for your best chances you should not rest less. .. But if you are desperate to send, rest at least one hour to be in your best physical shape. Mentally, you will just get more motivated the longer the clock ticks and your frustration for not climbing sets in.”