The Sabre really is a hands-on jet meaning it needs to be flown and trimmed constantly when changing speed, alt, heading etc, it not like the F-15 where you can "let it fly".
You'll get used to it with more practice. Take-off for me we very yo-yo like for awhile there.. :D
I personally prefer now to leave all dcs aircraft pitch curves at stock.
One thing I do every time I jump in a dcs aircraft (using X-52) is move the stick to all it's maximum travel limits, this de-sensitises the axis inputs, if i don't do this the stick is twice as sensitive as it should be. :)