[MaSnaka]

Priobe,
I can tell you a trust is an engineered support designed to be strong using the least amount of lumber. Economics and practical application apply here. Designed to support your roof and possibly your ceiling...NOT YOUR ENGINE OR BODY!! You need to modify or re-design (engineer) your suports to fit you specific needs. As Jerry stated he has joists doubled up to increase the support strength. Be careful or better yet consult a contractor in your area for some advice, someone who can look at your structure. I'm sure it can be done just make sure it's done right. Good luck!!