420: Dimensions of 420/421 Keels?

[Octopus]

If anyone has their 420 or 421 out of the water could they please measure the dimensions of their keels at the foot. I'm interested in the width/thickness of the keel at the bottom and the length of the base of the keels, because I'm constructing a low-level yard trailer, so that I can pull my 420 up a slip (there is no hoist in Scotland wide enough to lift Octopus).

For those that are interested, I'm hoping to use two I-beams, one under each keel, supported on multiple axles and wheels. The idea is to bring the boat onto the slip at high tide, wait for the tide to go out, place four hydraulic jacks under the bridgedeck and raise the boat up in the air, so the I-beam trailers can be placed under the keels, then pull her up above high-tide. This is at a remote location, so conventional methods are not possible.

Octopus, Lagoon 420 Hybrid
Isle of Arran, Scotland