A heb is for the roll. Wholemeal of course. It can weigh 60grams then the rest to be synned.
I am sure that is what you mean. I will see if I can find out how much per gram. Had a look if a hex wholemeal roll is 60g it would be 6 syns therefore every 10g over would be 1syn.
I was going back and forth from here to SW and ringing bank at same time
Hope it is helpful