I feel like I can write a lot more that I'm going to, because it would take some time.
Generally I'd say DII is the same mindset as DIII, except you have more money. Which means 2 main things, at DII you can actually afford to battle for players, but be smart about it, and you can be more aggressive about pull downs, both that you shouldn't be afraid to try it the 1st cycle if you think the player will give you a back up message and you can pull down from greater distances.
Also the quality of players and options out there are just better, and even though the top DIII players would all be great at DII, recruiting at DII you will have the opportunity for players who have better starting ratings and can make some impact right away. But you also have to raise your standards. For example, at DIII I'd play a player at guard with 60 speed, at DII I won't play a guard with under 70 speed.
And instead of writing all my DII strategies out, I may post some more for you later, I'll just finish by answering your ineligible question. Ineligibles, if you sign them, will either go juco and you will have to take a walk on, or show up on your team and sit the first season with no practice and no growth at all, but then play 4 seasons after. It's generally accepted that the more money you put into an ineligible, the more likely he is to show up. So if you sign him for $110, odds are he's going juco.
If you have any specific questions feel free to ask. I don't want to call myself the expert, but I have a few DII titles, and am consistently competitive.