One suggestion I have for you is to look at current/new models of boats that are similar in size to yours from Tracker, Starcraft, ALumacraft, etc and pic a floor plan/model that your really like and try to copy it or replicate it with your build. If you do this you can of course make even more modifications to the design or alter the design that you like to fit your personal needs.
Another couple of tips for you.....BEWARE this can and does become an addiction (not just a one time thing).
I know the urge to hurry and get it done so you can get on the water quickly is there. DO NOT LET IT RUSH YOU! Take your time, use good quality proucts on your build, do it right the first time. Look for good deals on stuff such as seats lights etc. Don't compromise. Build it the way you want it.
Finding good deals and doing this restoration or modificationon a budget is part of the fun of it. Anyone can go out and buy a boat.
When you get done with this and you have something you can be proud of, it will feel great! If you are doing it with someone it will be even better and an experience that you both can be proud of and remember for years to come. Not to mention enjoy it together for years to come.
Good luck!