Probably many jets use 1nm=300' at finals. At distance and height, this may change.
1nm to lose 10kt works rather well in level, on des I reckon probably have to use at least 1.5nm.
All these is without accounting for drag devices which will most probably come in use when caught high.
B737 can really drop. It is more than double the drop rate with 'everything' down. 20 000' 30nm. Impressive.
But I guess the other option would be to drop with speedbrake then configure on level?
Thanks for the input guys.