Flat plates are an absolute must, and slacken off the springs as far as you can do make sure they pull out straight as stated above, try frontera plates you can get an extra one in = less spring tension required.
As an aside have you ever put a 175 frame next to a 350? there is quite a difference in size, (note swinging arm in picture), top tube is 25mm smaller in length and lower too.
They may have had nothing in the fuel tank or water in the tyres so who knows what the real weight is?
I do Know theres not 5 speeds in the box though!
There has been a minimum weight in wtc for a few years now. Was next to Bous bike when it was weighed in France 2012 and it was just above the limit at 67kgs.
It was not the "lightness" of the Bulto which led to the addition of lead but the weight distribution and the fact vesty felt the front came up too easy with his weight back looking for grip, I believe.
get some training or advice, where are you? its easy to speculate on here but the reality maybe a simple fix.
My guess is you are relaxed too much because you set out and concentration is part of that.
