Eric, what's you current bouldering ability?

A little something...I always have a hangboard above the most traveled doorway in the house. Every time you walk under it do at least one pull up. This adds up real quick.

V7 or so.

Just come to Rumney and tick off Bottom Feeder! (5.13a/V7): www.mountainproject.com/v/bottom-feeder/105869028

Sounds like you're bouldering more than hard enough to send Goliath, and it also sounds like your PE training is paying off. The major constraint seems to be that you have limited attempts.

Most of us have been answering in generalities, but clearly you are quite close to sending your project and it's well within your ability. However given your time/attempts constraints, you need to know how to be so ready for your climb, that you can confidently finish it off. You're doing 60-move endurance problems for an endurance route, and it's well within your bouldering ability. You're already doing highly specific training, so how can you do better?

If your goal is to send Goliath, up the specificity and intensity.

Do you have a video of you climbing Goliath? Take one next attempt and pay attention to the number of moves per mini-problem, and how frequent the rests are. Even pay attention to the approximate style and grade of each small boulder problem, and mimic that on the wall. To up the intensity, make the problem a little harder than the route, or wear a weight vest or something. I'm guessing you've got a high intensity going already.

I took this to the extreme working on a project back in October. The crux was 10 moves long, on strenuous (if good-sized) underclings. I took a video and designed a training program approximating the force needed for each move, the time at each position, the time between movements (even allowing for clipping, etc.), and the type of grip position I was using. After a few sessions I managed to surprise myself with a one-hang!

Artificial specificity is the weekend warrior's equivalent of projecting for multiple days during the week. It makes you get weaker in some areas, but it hones your skillset for one project.

My folks actually live quite close to Rumney so I may take your advice on my next trip back east. I have only been to Rumney once, for a couple hours, and only remember the Flying Hawaiian.