First time plug and mold making

Hi all, I'm about to start on a new project to build a plug and mold for a bench seat for a 15' Boston Whaler. It's so I can make a seat for two boats, possibly more. I have a design of what I would like to build, see attachment.
I have lots of fiberglass repair experience, but never made a mold. Have kind of an idea, but a couple things I'm still not sure about.
The main thing is finishing the bottom of the mold and eventually the seat to have an even and smooth edge.
I know it's probably too much for someone to type in a reply, so can you recommend any write-ups and videos I can look at to get a better idea?

 

if it simple shape just make a wooden mould and no plug !!!

is it just the seat part you wanting to make ?? not the bottom ??

its possible to make a wooden mould and Duratek it!!, saves making a plug and then having to make a mould just to make one part !!Duratek can be waxes and make the product from no sweat !!
is it really necessary to have those square chunky bit on the outer ends ?what purpose will they serve ? plus it makes a weak part because of it shape if its made as one piece in a mould and with a couple of heavyweight buddies you'd end up with stress cracking in the gel coat eventually on both ends !!

 

Yes, it's just the seat part. The bulky pieces on the sides will serve a purpose. The plan was to make them big enough to mount a rod holder for trolling. The height is needed so that the reel won't hit the side of the boat and the length fore to aft, I did to give more resistance to the leverage being applied while trolling. Plus, it kind of matches the console

I've already started making the plug out of 3/4 plywood.

 

Ok just some basic things to keep in mind ! when glass goes round a right angle corner (any corner) it is always trying to close up so the more corners you have the bigger the problem you will have !!
Remember the mould will need draw on its to so the product will release easier or make your mould in two pieces !! remember the mould will draw as well as the product you make so you could get double the draw you really don't want !! because the shape gets worse with age so look at all those right angled corners and think long and hard what's it going to look like in a years time !!:idea: