Yes, some. It's impossible to even know all of what a person says, let alone fact check all the statements. But 'some' doesn't mean the picture isn't complete enough to draw some conclusions. Those 'some' statements aren't exactly non-representative of the claims he's made politically. While a case might be made for a sub-set of the set not being representative, there really doesn't seem to be much of a way to slice up the set to come out with him 'ahead' as far as honesty goes.
Both in a fashion. How important and extreme the lie is, is a value judgement. That they're lies and that they are well out of line with reality is much less so. How egregious Hillary's lies tended to be is also a value judgement, but that doesn't mean it's without support.
It isn't just opinion, even if opinion does inevitably enter into it.
I believe the objection is to the insinuation that somehow the opposing views are therefore equally supported, or that it's all a value judgement. From the best evidence we have, Trump is far and away the biggest liar. That's not to say value judgement doesn't ever enter into it, but that the parts that are value judgements doesn't invalidate this conclusion in any meaningful way, nor is it support for the opposite contention.