I think you're going to need a real stroke of luck on this one! There's loads of conflicting text, including the 'fact' that there were two sister ships (Meteor and Lightning).
Allegedly the length of PS Comet was over 100ft and the only Meteor I could find about that size was used as a ferry (See attached)
I've checked as much I can through NMM and National Archives and the NA have early files, including drawings, from Boulton, Watts & Co.
Another doubt area is that the designer Oliver Lang had a son Oliver Lang (1807-1867) who was also a naval architect for the RN. Father and son were involved at Deptford and dad trained son. The anomaly arises in that almost all paddle tugs, before and after, appear to be considerably shorter than the 115ft. In fact most of the illustrations for the period from 1815 to 1860 or so are remarkably similar. There are a decent set of drawings on the NMM site for an 1848 tug at 72ft if you want a generic one (See attached)
Very Good Luck Indeed!
Tony