yea -7
That offset calculator is good for ease of working out fitment but really you can make anything fit. If you look at works1200's old sedan which had 13x7 with a zero offset his wheels poke a sh*t load more than mine which made for awsome wheel fitment. He was running ae86 suspension etc which pushed the track out heaps. Kinda like running a very low offset with lots of camber dialed in.
Obviously ride height, tyre profile, wheel offset and camber setting has a lot to do with good wheel fitment like any other car out there.
As far as offset is concerned, with standard spring perches and with a half decent ride height, i found that a 0 offset on a 13x7 is pretty close to the most positive offset you'll want to run. Could probably get away with +4 or so but anymore than that and you'll be rubbing the perch. This is all taking into account that the tyres arnt ballooning over the rim.
Heres a picture of the inner of the rim clearance to the strut. As you can see, theres sufficient clearance but not tooo much to play with, i think about 10mm from memory.175/50/13 tyres

Theres quite a bit of room to play with on a b110 in the front. On my ute the lip is level with the tyre and i havent rolled the gaurd at all. Just bent up the inner lip so it doesnt cut into the tyre if it does so and added some camber. Never rubbed.
On the rear ive pretty much done the same but with a little bit of a push on it because my rear is very soft for some grip.
If you're looking at 14's you have to realise that itll be a bit more work to get the car sitting at a nice height because of the larger rolling diameter, dependent on tyre size ofcourse.
IMO i would always start with a rim/offset i want then go about fitting it. With the right height/spring stiffness, tyres, camber wou'll be on your way to an awsome stance.
If you ran 14x6's, to get the same poke as the 13x7's you'd need a -20 offset but will have 26mm more clearance to the strut. If you wanted an 8inch wide rim the same poke you'd need a +6 offset but then would have 26mm less clearance to the strut meaning you'd have to add spacers (same as reducing offset without added dish/taper) to gain some clearance and would end up with something like a -15 offset to clear but will poke another 21mm.
So if it were me and i wanted to run 6's then id find the most negative offset i could and make em fit. If i wanted to run 7's, well id do the same really but something in the 0 to -10 would suffice.
These are all my opinions, dont get cut up about em.