Home Improvement Questions? Ask a Handyman for Answers
The only thing that meets all your requirements and will be consistent with a craftsman style building would be to use 2 x 2 pressure treated balusters and either a molded pattern railing or a treated 2 x 4. You must use ceramic coated screws or stainless steel fasteners. I don't get the strength question, balusters must be spaced so a 4" sphere cannot pass between them. Spacing the balusters closer together adds interest to the balustrade at minimal additional cost. Once the treated wood has weathered for at least 6 months you can paint it to match the existing trim.