Dragon Ball, DB Z, DB GT/How much stronger is Super #17 is compared to SSJ4 Goku Full Power?
Q1: How much stronger is Super #17 compared to SSJ4 Goku Full Power during Super 17 saga?
Q2: How much stronger is Syn Shenron (Yī Xīng Lóng) compared to SSJ4 Goku Full Power (During Super 17 arc, before the ultra limits power up)?
Q3: How much stronger do you think is Ultra SSJ4 Goku (past his limits) compared to Syn Shenron?
Also I haven't forgot to rate you for the SSJ2 Vegeta question, I have a follow up but forgot the question.
Most of these are all really hard to say, since GT power scales things in such awkward ways and you don't get any comments being made towards exactly how much stronger one character is over another, just that "so and so" is stronger than "other so and so".
1) You're probably looking at a gap of at least 20% or so, as Super #17 was basically outpacing him and steadily outdoing him in every regard. Goku wasn't able to get the upper hand at all during their fight, and #17 was delivering attacks that Goku was able to survive, but was having trouble coping with.
2/3) Despite how severely it seemed that Goku was being beaten on and, in turn, how badly he was able to beat on Ii Shinlon, truthfully the gap between them should be within the amount of ki given to him by Gohan, Goten, Trunks, and Pan, as he was weaker than Ii before they gave him their ki, but was superior to him after. Perhaps one of the reasons Goku was doing so bad to begin with was because he had depleted some of his strength from his fights with Suu and San Shinlon, and that Gohan and the others restored him back to full ki in addition to supplying him with extra.