Widewing,
I don't know where you got that info about the hill being unoccupied. At the time that Gen. Ewell was told to advance if practical, at that time the hill was empty, he thought about it to long. After fierce campaigning with Jackson you would think that Gen. Ewell would have recognized this fact, but alas he is no artillery genieus as his commander.
Coddington's "The Gettysburg Campaign, A Study in Command". This is the "Bible" of Gettysburg studies. Begin with Map 6, and then begin reading on page 297, paragraph 2.
After 40+ years of studying the War Between the States, even doing my Masters Thesis on the Gettysburg Campaign, I've read just about every account, every official history, every study and analysis of the battle. Add to that countless books and articles.
Ewell was told to attempt to take Cemetery Hill (no mention of Culps Hill in Lee's order) if at all practicable. I'll say again that Lee had very poor intel of the condition of the 2nd Corps and what they were facing. Ewell also commented that he wanted to push up the hill as soon as possible. So, once again, I will state that Ewell's Corps was in no condition to do so for at least an hour, probably much longer. Rodes units were largely wrecked... Early's Division was completely disorganized by pursuing the 11th Corp through the town. Units were scattered all over the town, regiments and brigades would take time to reform to the north of the town. Intermingled with the Confederates were hundreds of Union prisoners. Smith was just arriving and Johnson was two hours from being on the field. (Edit: I forgot to mention that Smith's scouts reported that a very large body of Union infantry was seen to be advancing down the York Pike, which would put them on Ewell's left flank, which was largely hanging in the air. This startled Ewell, who ordered a scouting party out to confirm the sighting. About two hours later, they returned and stated that large bodies of Federal troops with artillery and ammunition trains were indeed advancing, but on Hanover Road and the Baltimore Pike, which would not place them on his direct left flank. Few could argue that Ewell was timid in assaulting either hill when there was a real concern that his left flank was in danger.)
Lee saw the high ground and knew that if the Federals reinforced the hill, pushing them off would be very difficult. So, he passed his order onto Ewell via Walter Taylor.
Aside from Coddington, two other books that are useful and easy to read (Coddington is not an easy read) are Stephen Sears, "Gettysburg" and Noah Trudeau's, "Gettysburg, a Testing of Courage". These three will present a definitive understanding of the battle, its tactics, strategy and leadership. Moreover, the second two are extremely well written and thoroughly entertaining. What all three also do is cut through the mythology of the battle, both Union and Confederate.
