Cool!

Glad you decided to build it. Although I'd have to agree with Mike's Spring Air recommendation, you might want to consider electric retracts. Back in the day, Kraft Multicon's were the thing to use. Today there is at least one brand if not more but the company name escapes me. A little web seach will turn them up.

Yea, on a trike system of this size avoid mechanicals if you can.

Cheers, David.