Utri007 - Thanks for the tips, and for the link. I've been following along on the thread unfortunately have been too busy to respond. In any case, with the new download and those options in-place, it is a big improvement in performance on my system. 25-35 seconds for amiga.org, 3-6 seconds for google.com (I reloaded these pages a couple times), etc. Scrolling is also significantly faster.
Unfortunately more complex pages still seem to take an age ("fetching, processing"). cnn.com took almost three minutes to load.
Wikipedia took 673 seconds (and boy was it ugly in all Topaz font). But hey, we're getting there. Also we're now in a realm of pages that IBrowse can't even load - I tried bankofamerica.com, for example - IBrowse just throws an error about "outdated encryption" or something along those lines. NetSurf at least loaded the first page of it.

Aminet also works and I was able to download files (yay, new version of Peter K. icon library!

)
I concur with the bug about it freezing up now, however. As a test I left it sitting at one page for about an hour while I went off and did other things, and when I came back to it it was completely frozen. Wouldn't exit, wouldn't refresh, etc. The system was still operational, I could load other programs, but no sign of life from NetSurf. Had to give it the three-finger-salute to shut it down.
More testing required...
Chris - any possibility of reaching out to any of the original IBrowse dev team? I know at least Oliver Roberts was still active in the Amiga community, with his WarpDT's (which are great, btw). I vaguely recall hearing something about him having an update for SSL, as well. Perhaps he could help you with your datatype issues, at least?
Just a thought.
My .02 cents, it is a real shame what happened there. They had a great browser, and then just

Doesn't make sense to not even be accepting registrations anymore, since I'm sure at least a few people would like to pay for it rather than download a pirate copy...

Another probably obvious question for Chris - since this is built off NetSurf source, there's no possibility of you ever going commercial with it, is there?