I have a Mako 12 Angler left pedal mount with sheared bolt and cracked recessed bolt housing.
Hi
1) For patching would see article and video here:
Also may be able to just put a patch over this hole with something like Gator Guard.
2) Unfortunately the factory doesn't' have instructional info for for mounting the new clamp modification kit, but if you can line up the clamps and drive together against the hull (impulse drive hole area) should be able to mark the holes to drill and install the bolts. The underside can be accessed via the front hatch port. There are washers including but would also recommend adding/ wiping with your finger some marine silicone around the bolt to form a waterproof seal.
Because we are not the ones installing it, we can't guarantee this will work but if you are reasonable handy then should be ok. Alternatively you can take it to a kayak shop or marine shop that is good with boat repairs and they should be able to install it for you.
Hope that helps,