@matthewfraase, you're getting plenty of good advice in surfing here. Let me see if I can add a little by consolidating some of it.
#1 ballast is what builds the wave. The more water the hull displaces the larger the wake will be. The location of that ballast in the boat will effect the shape of the wave. Surfing requires accentuating the wave on one side. To do this on a Yamaha you'll need to focus the majority of the weight in the rear on the surf side. The custom swimdeck bag is the ideal for this, it puts the right amount of weight in the right place. Although having additional weight in the bow is going to improve it even further displacing more of the hull and increasing the length of the wave. Your 400lb bag on its own will have a minimal effect on its own.
#2 Jet drives make messy waves. The devices created specifically for the Yamaha's like the wake wedge and wakebooster (aka wake enhancer) work best because the target the jetwash specifically. The generic shapers that stick to the hull are less effective or do nothing on jet boats.
@jcyamaharider is the creator of the wake wedge. In my opinion, his device with the proper amount of ballast is the ideal setup. It has offers the cleanest wave with the most push and offers the ability to adjust the pitch and effect on the wave.
The wakebooster has also proven effective. By comparison from what I've heard and seen, the WakeBooster directs water passing along the side of the hull and redirects it across the wake. This does a reasonable job shaping the wave but also introduces a lot of air which actually softens the wave some giving it less push.
Surfing without a shaper is possible, but you have to cheat a bit. Diving in a gradual circle surf side will accentuate the wave on the inside of the turn. You can also offset the throttles, powering up on the non surf side and down on the the surf side.
#3 Speed. Your typical surf speed behind your Yamaha should be between 9.5-11pm. The help of a GPS based speed control system like Ridesteady wil be a big help in all water sports. It's awesome!
#4 board choice can be criticaleven it covers to smaller waves. Boat info, ballast setup, rider weight, and shaper are all factors.
As others have mentioned, I have a side hustle. As a watersports dealer. I've helped outfit many members here with boards and other equipment. I'd be happy to give a recommendation. I'd just need a little more info. We have a great buy on some last year model Slingshot Coasters right now.
Here's a link to our site:
No matter what boat you have we have a wakesurf board that can surf both large wakes and small wakes. Beginner to advanced riders. Let the fun begin with Transom Watersports.
www.transomwatersports.com