do the V-rakes run off hydraulic pressure all the time or just how do they work, both the rollobar v rakes and the wheel rakes. I saw one video that said the wheel rake rake off of the crop as you were driving. I'm really confussed on these things. I really like the looks of the rolla bar V rakes best but do they have to have constant hydraulic pressure to work or pto driven. Man I did not know it was this confussing. Which rake does not leave lots of hay lying behind and would be best for hilly ground here in WV. I have a Massey 265 or an 8N to rake with. Help!!!!!!!!!!