i've never bolted one on before, but it does not look hard. the trick is to go through the reel first. the electric motor is very unforgiving. if the drags stick, the powerful electric motor will shred the gears quickly. here's a page from the electrmate website.
http://www.elec-tra-mate.com/ordersports.html#312HS which reel were you looking at? i presume you were looking at 80# spectra? a 4/0-sized penn 113h would probably work just fine. alan