The h is, in "standard Madarin", is very similar to the English H. (I think it's ever so slightly more "throaty"). There is no difference, really. There should be no difference in the "h" sound of the words you've written down. They are all uniform. 

Listen to these (I have a foreign accent, but my pronunciation is alright):

1）我很好 https://www.dropbox.com/s/mcvxjnkzgqri0ap/1.mp3?dl=0

2）我喜欢你 https://www.dropbox.com/s/kg7afvdmmipjudy/2.mp3?dl=0

3）我很喜欢你 https://www.dropbox.com/s/sggf7pnx7qp0wy5/3.mp3?dl=0

4）欢迎你 https://www.dropbox.com/s/ijolttg3dtyjagi/4.mp3?dl=0

Now, people from Beijing and the north in general (especially 河北) will often make this sound much harsher:

5）这个很有意思！ https://www.dropbox.com/s/o10hp63ombwaw85/5.mp3?dl=0

6）很久很久以前... https://www.dropbox.com/s/gg02iyn203mrag2/6.mp3?dl=0

7）这是怎么一回事？！ https://www.dropbox.com/s/zxu7qwrpx297hab/7.mp3?dl=0

This is not "standard", but it happens.