just recently upgraded to riva metal washers,and installed a groco strainer,and a tow valve. was going to install a bilge pump as well.........

I was looking at the attwood stainless straight barbed thru-hull fitting,but i think the hose size is 3/4inch(I.D.) but not sure which flange diameter should be used.
and was looking at rule-mate 500 model #25S automatic 12 volt.......not sure if this would be the best choice?

any other modifications that would be critical for reliabilty or safety issues?