If you are like me and have one of the older EQ-35 Pro's (mine is a rebadged William Optics) then you are probably familiar with the issues with the DEC axis stiction/tightness.
My total RMS was never below 1.5 at the BEST of times, and I even followed the guide on "tuning" it that I found out on YouTube.
The issue for mine was not so much loosening the nut, but the junk for grease that they used to grease the instrument with. And over the years, it only got worse.

The tools I needed were:
1 - 16mm box end wrench (12 point worked best)
1 - pair forceps (for putting the washers on and holding the nut when reassembling the DEC axis)
Allen wrenches (1.5mm, 2mm, 4mm and I would suggest, if you have a kit with them all in one flip handle, get at least a 2mm standard one)
Citrus based degreaser (I used ZEP)
Grease (I used Mobil 1 synthetic general purpose for the bushings and Krytox for the gears)