I'm afraid I have no tips on mobile browsers, as I just use whatever is on my BlackBerry. The initial load is certainly slower than the previous forum, but then it's a little more image-heavy, and the menus are more complex. I'll see if I can tune the images to further reduce the load. The output is already compressed, as with ICB, to minimise the download requirements.
I won't have time to make tweaks to the overall theme for quite some time, but in the long run want to look into a mobile version of the forum. This was raised in relation to ICB in the past, but as it was going to die there was no point in wasting time. For now, I use the zoom facility of my mobile browser to click on the links <!-- s:) --><img src="{SMILIES_PATH}/icon_smile.gif" alt="

" title="Smile" /><!-- s:) -->
EDIT:
Have made the Forum and post links a little larger. See if that helps Wallacebiy