I used to do DL first.

Switched to put it at last since I visited a random gym in Kuantan, the boss told me about taxing (if do at first) and also the required mentality when you do it last. I made noticeable improvement in DL since then.

DL and Rack Pull~ I do them alternately. Seriously my most favorite exercise period.

Try it and see which works for you. And low reps,too