Well, DL hasn't had a "chart" in many years. Partner metal award levels to/from US/Canada were harmonized with Delta metal levels last fall and they will just book into lowest available DL metal award level. These levels are variable by advance purchase, roundtrip booking w/min stay, day of travel, and can have seasonality requirements. Basically, cheapest levels will generally require booking at least 60 days in advance as a roundtrip booking with a 7 day minimum stay and mid-week travel. Two one-way bookings will be higher than a roundtrip in almost every instance due to the cheaper award levels requiring a roundtrip booking with 7 day min stay. Award levels are also variable by route, cheaper more competitive routes like BOS-LHR have lower priced D1 awards than routes out of expensive hub hostage airports like DTW, MSP, and ATL.

As noted above, award levels to/from Mexico/Caribbean have not been changed in quite a few years and you can still get D1 awards to/from Europe for as low as 75K miles each way (but availability at that level will be sparse for higher demand periods).