By "user to root privilege escalation", I'll assume you mean leaking kernel data without root, since this attack doesn't directly allow escalating privileges at all.

For variant 1, you would need to find some legitimate kernel code, accessible by syscall, that looks at least somewhat similar to the example in the Project Zero blog post:

    if (untrusted_offset_from_caller < arr1->length) {
        unsigned char value = arr1->data[untrusted_offset_from_caller];
        unsigned long index2 = ((value&1)*0x100)+0x200;
        if (index2 < arr2->length) {
            unsigned char value2 = arr2->data[index2];
        }
    }

In practice, you may not be able to find something nice like "((value&1)*0x100)+0x200", but even if it simply used 'value' as an index, you would be able to at least narrow it down to a range. Other code patterns may work too (and potentially be more powerful?), e.g. conditional branches based on 'value'.

For variant 2, see caf's answer to you in another thread.