New to Hammock Camping. Need advise on starting

I am looking to get into hammock camping after nearly a decade of tenting. I have been reading posts on here and ultimatehang and have the following questions:

1. Before I drop money on a dream hammock I was looking to test hammocking with a cheaper ENO. However I have not been able to find anything around 11ft (I'm 6'3" ~250). How much will my experience be effected by getting a 9'6" hammock?

2.Underquilts seem to be relatively expensive, will I be able to get away with a 15 degree sleeping bag with a foam pad in 50 degree nights?

3. How much extra warmth do overcovers actually provide?

4. general tips/advice