Code wise...3 #3 thhn's in a 1" EMT do fit, but just barely ~
1/2" = 1 #3
3/4" = 1 #3
1" = 3 #3
1 1/4" = 6 #3
...that 1/4" makes a HUGE difference!
I recall a job I did where 11 #10 XHHW conductors were pulled in a 3/4" RGC for stub-ups(code allows 11 @ 3/4")...the rope broke once, the guys were POed at me all day...and it took 4 guys just to pull ~ not including the guys at the feed end. After this fiasco(which took about a 1/2 day to go just over 100'), I had the crew start running "extra" 3/4" conduits overhead.
The amount of effort that was required to get the wires in was not worth it.
For you, a small tugger(gets attached to a RA drill or hole hawg) might be a viable alternative...pay for it once, use it over and over again.
