looking at different contact lenses some come only 8.6 & 8.5 BC?? does it matter when trying a new namebrand ?

Of course it matters.

But not just the base curve determines if a lens will fit right.

Even if you are wearing an 8.6, a different brand still in the 8.6 may not fit well at all. Every different brand has a different water content, is made of different materials , and that makes them all fit differently.

When someone is interested in a new brand for some reason , we ALWAYS get trial lenses first to see how they will fit , and very often , the brand they thought they wanted just won't work.

So, first we have to know what range of base curve SHOULD be the correct one for you by measuring the curvature of your corneas , then trial lenses in that range to find the best fitting one.