If your wave is thigh high that is a pretty good medium sized wave. Waist-to-belly-button is above average and I have not personally seen the bigger ones but they look monsterous!
I agree you should weight the whole rear of the boat and then weight the surf side some more. Otherwise you else up tipping the boat a lot but the wave isn't that large overall (need to displace more).
I weight mine with 500 across the rear, then add 700lb minimum to the surf-side and its pretty good.
For me personally, my wave really gets a lot longer and better shaped when I add about 300lbs to the bow. HOWEVER, the bow sac is pushed all the way to one side up against the hull (as opposed as in the center of the bow). It is also pushed all the way towards the main cabin as it will go (as opposed to being pushed up towards the nose).
Since everyone agrees Supras take above-average belly weight, I do think it's a bit odd more people dont use ANY bow weight for surfing. You have to get it placed just right but I think it helps.