Fitting looks pretty suitable. Excepting for something very unusual, it should last the rest of the boats natural born days. 8 machine screws, i think would be more than ok for this.
Selden in many cases uses 6 or 8 1/4 rivets onto a fitting with a way smaller footprint.
See here :
http://www.seldenmast.com/ebrochures/ENG/index.cfm Page 80 - 81
Cheers, just me 2 cents....
