I have a similar problem with slow scrolling on my Palm IIIXE, but it still works, just a bit slow at times. In general the Geo2Ozi files (haven't upgraded to GSAK yet) are slower than the ones produced by GPXspinner
There are a number of differences in the html produced by the two programs. I think what it really gets down to is what iSilo does with the html.
GPXSpinner pages are basically the contents of the table with a html header and footer added. This is OK in cases there there is no background image for the page. In a situation where the page has a background the line
is in the html and causes the image to be tiled under the text, making it difficult to read on a computer.
GSAK keeps the table structure so the offending image remains as a border, outside the table.
Other differences are in the difficulity and terrain. GSAK uses stars, GPXSpinner uses numbers. The images have to be moved when scrolling the page, this could be an issue on the slower Palm devices.
I could suggest that Clyde insert a link near the top of each page to jump to the nearest caches list on that page. That would get aound the issue for those just wanting to see the nearest caches.