Use the blue springs in this kit with the factory center plate and advance weights. Tack weld a stop plate that will only allow the pull arm on the vacuum advance to move .125(1/8") this will give you pretty close to 12 degrees advance provided by the can for a cruise of about 46-48 assuming your provided numbers are correct.
https://www.summitracing.com/parts/c...00-1/overview/