Colon SET taxi costs

We have a day in Colon and most of the ship tours aren't very interesting to me. I don't necessarily need a guide, just transportation. I understand there are taxis that charge flat rates. Anyone have any idea of the cost for 2 people to Agua Clara and then Portobelo, with waiting and return? (Or is there an hourly charge?) I've searched but can't see any mention of current prices.

You might be able to just negotiate a price for what you want, which could turn out a little cheaper. Although it has been awhile since I have had any local taxi experiences I would think you could use $20-30/hr as a guide plus the cost for admission to the Locks.

from the few references I've seen online to SET pricing (which are more than a year old), it seems $20-30 per person per hour is closer to the going rate. That's what I'm trying to confirm.