I did not find the suntracker to recline adequately for Zenith viewing. IIRC there were three positions only.

I bought a similar looking non-swivelling beach chair from walmart that recline to horizontal, and I was able to rig up a swivelling platform using lazy susan bearing. Toal cost was $25 for chair + $15 for hardware (compared to $90 for suntracker). 'will post picture soon.