Most of us are using Hoosier race slicks. Fronts are mostly 7.5x20x13 on 8" wheels. Rears are usually either 9.0x20x13 or 9.0x22x13 on 10" wheels depending on gearing. Finding used wheels can be a challenge. You might check with Diamond Racing Wheels for inexpensive new steel wheels. I use Diamonds for my rain tires. Don't know a source for used tires. If there are any C Sports Racers in your area, they use the same size tires.
Also check out the SoloVee forum at formulavee.org/interchange
2002 Mercedes C230k, retired, 2005 Nationals STU DFL
1969 Beach Solo Vee and 1985 Lynx B Solo Vee