Don't do that - it will cause more problems than enough - preferential
corrosion  by electrolytic reaction. You will most likely still have the
bolt and a large hole.

Cadmium plated bolts not SS.

Someone else may want to comment on this.

Sizes 1/4  5/16  3/8  AF  in various lengths. from 1/2" long to 2" long.

I keep boxes of cad plated in each size H/Tensile bolts, nuts, flat and
spring washers and grab whats required for the job. Would not know the
exact quantity of each but buy a new box when and if required.

You should nominate where they go or where you want to start then ask.
What does it say in the workshop diagrams there's a clue.

Why?

There are very good reasons, quite apart from cost, why no major car
manufacturer uses stainless steel fasterners for most applications.

Stainless is prone to fatigue failure and crevice corrosion, and you
won't find high tensile stainless steel bolts with equivilent
performance in the same sizes.

Basically pretty much everything is UNF thread, except things which are
screwed into alloy castings such as the gearbox case, which are UNC.
Anything you can put a 1/2" spanner on is 5/16" UNF or UNC, a 9/16"
spanner means a 3/8" bolt, and a 7/16" spanner means a 1/4" thread.

Whilst there are some applications on the Mini begging for stainless
fasterners, be very careful about fitting them to any mechanical
component. For example definitely do not use stainless fasterners to
mount your brake calipers!