Google Maps 3D Hack - get down to eye level

I had an enoyance while browsing the new 3D landscape feature on Google Maps regarding how close I can zoom in. Histon now has the 3D view thanks to it's proximity to Cambridge and it's rather lovely to be able to see my neighbourhood in stunning graphics (yes, I realise this will be outdated in a few years time and you dear future reader will chuckle at how impressive we though this was). The manual controls (ctrl+click) allows you to drag the view round freely and zoom in and out with the mouse wheel. But it seems that you can zoom in and tilt only so far, and less than I think you used to be able to. I did some brief googling to see if there was a way around this (or indeed anyone talking about my observations) but nothing came up. One lifehacker site mentioned that you used to be able to manually edit the URL of an old version of the website. This inspired me to check out and have a play with the new URL. Low and behold - success, if somewhat fiddly.
Take the URL: https://www.google.co.uk/maps/@52.2509106,0.1046145,94a,20y,25.28h,60.55t/data=!3m1!1e3.

Look at all those interesting numbers in the URL: @52.2521678,0.1056801,5a,20y,135h,83.59t/data=!3m1!1e3, here's what I think they mean:
@52.2509106,0.1046145
this is the latitude and longitude in a North East postive system (-ve values are South or West).
94a
this a is for altitude, I assume it's in meters. Setting 3 gives a good eye level view, below that and the screen starts to clip the terrain. Large numbers take you off into space.
20y
this I can not yet work out. It's something like the zoom level, but the API converts it into a change in elevation.
25.28h
h is for heading taking a value from >0 to 360 (north, default).
60.55t
this is the view angle with 180 being straight up (mostly sky), 90 is horizontal and below is tilting down. Above 180 gets reset.

google maps 3d street view histon. Nick Bailey
Red Lion pub in Histon from Google Maps
google maps 3d street view histon. Nick Bailey
The Boot pub and Coop in Histon from Google Maps
2015-06-25