Just for anyone looking at this thread for the first time:
What the OP did with his seatpost was fabricate (very cleverly) a copy of a Profile Design Fast Forward seat post. These things look pretty ugly, but they´re effective at what they do, which is to change the seat post angle from the common road bike 73 degs to a steeper +/- 78 degs, as favoured by triathletes.
PD make two versions, the alu one is available in 27.0 and 27.2 mm sizes, the carbon just in 27.2. If you ride an older bike with a narrower gauge seat tube then you might have to make your own, otherwise flip your existing seatpost round (if you can) and slide the seat forward.
The second-hand market for these seatposts is very strong, so you should be able to pass it on in the future for what you paid for it, should you upgrade to a tri specific bike.
Alu version
Nitto 66 seatpost - similar idea
Valdora Ti seatpost - a pricier option.