Minimum of a 60" spadetruck is what ya need.   Walnut should be ok, Oaks are tuff as heck to move, helluva taproot.  Should work, best time is when the leaves are off (now).  Following year ya better be ready to try to drown the moved trees with water, never let em dry out.

Year after water half as much, third year they should be fine unless ya have a drought.   Little food wont' hurt either.....NPK.

Don't expect them to look like they do now, it'll take a couple years for them to get over their shock, but should be fine for the rest of their lives.

If any question about size, like your 8-10 is more like 12-14, go with a 90" spade, more money, but better your trees live.

The dutch boys down in Pella make a great spade.

good luck