A question on dips

Today I tried out single bar dip at the gym here, it wasn't bad at all, my legs were always in front of my body though, I guess it's for balancing. Maybe I didn't go far down enough, maybe my body was touching the bar? Then I tried Russian dip and I could not get up once my elbows are on the bars, do you rock your body forward then push? I wonder why the book gives the single bar a more difficult rating then Russian dips.

For regular dips on PB I do 10-12 per each set for 4-5 sets. I can probably do 30 of them in a row though never tried. I want to build more strength, what are my options besides a weighted dip?

Yes you do. You may have to play with the pb setting for Russian dips

To develop strength, start doing bulgarian dips on the pb if you can, and if you have access to rings, do dips on those. It makes them a great deal harder. Its all about moving up progressions when you go past 8-10 reps in an excercise.

Do not discount the Korean dips, even for only a set or two. Your strength in a position that requires more active shoulder flexibility will thank you. So will your joint health.