With all that was said and if you decide to go through with using it, as was said by a couple of the members: 250-300mg of the extract per 1g of dmt is a great ratio to use.

EDIT: I should've payed more attention to the title 'enhanced leaf'. 1:1 ratio of dmt:herb is the way to go imo/ime. Adding the amount of harmalas stated above though will make a nice changa, though if you want just enhanced leaf then just do the 1:1 of dmt:herb, or you could also add a bit less harmalas per 1g of dmt used - like 150-200mg harmalas per 1g of dmt - that ratio would be a very light-harmalas blend.