Well I'll be damned! 64 with 16 works fine and gives 3.6 ms RTL at 44.1.
Thanks for pointing this out Steve!

I can still only run one or two amp sims (S-Gear) like this till it crackles a little - then I have to bounce or go back to 128/48. 128 with lower safeties also works fine now - and never used to - so this driver ver is definitely optimised better

So it seems some combinations of buffer/safety are better than others, and bigger isn't always better ;-)

Someone else pointed it out to me as well. I figured if I'm getting clicks at say 64/64 then 64/16 has got to make things worse so I didn't even bother to test. Glad things are going well. 

That's exactly what I thought ;-)

SPLAT 201702 build 45 and new MOTU loads working good with my Ultralite mk4.  Site said to update firmware so I used the latest, then ran the new drivers.  Tested with a two recent projects, one without much fx and another with heavy fx and instrument tracks... ASIO set at 128 samples/48 offset (8.0 ms roundtrip) and perfect on lite mix, got a bit of clicking noise on the heavy fx mix.
still can't run the MOTU interface in Chrome, though... asked MOTU and they don't understand it either.
 
edit: and steve0, that WAS an improvement on my heavy mix when I lowered the offset to 16.  amazing!

This may or may not help but it worked for me.
 
With Chrome, you can't zoom the text size too large or it will not work. So open a web page, say Google.com, and hit CTRL - (minus key) to reduce the size of the text. Close Chrome and then try the MOTU interface. I had the same problem a while ago and it was driving me crazy. 
Zoom to 80 % works for me

nope, went down to 50% and it still wouldn't load.

Maarkr
nope, went down to 50% and it still wouldn't load.

Rats!
That is weird.
Only thing I can think of is maybe some extension in Chrome  that is causing problems.
Mine works here, no Ethernet hooked up though.