ok your images and method are very conviencing! :)

i will study that and see if I am wrong somewhere on the lines following

""But seems that is not the same start concept
I have several vertical half sections given for any reason (say for a boat)
you have several complete horizontal sections
does these horizontal sections can be done without make first the Loft & fillet or the vertical sections
And maybe not so easy to just change the angle of the Fillet than change all sizes of your section curves""