This is a useful thread as it goes to the heart of the delta between the artificially constrained world of certification and the dirty real world of ice, slush, fatigue, etc., etc. ..... at the end of the day, commanders are paid to make judgement calls ... if your level of conservatism is inadequate on the day, expect to be called to justify your actions at the enquiry.
An easier, less stressful, life is enjoyed by bank clerks ...
As a far wiser commander observed when I was but a new F/O on a day of much thunder, lightning, low minima, etc. .. " at the aeroclub, they wouldn't let us go flying .. now they make us go ". This is one of the worries associated with a general deskilling of the flying workforce ...
In respect of the initial question, if
(a) Vmcg is not a problem
(b) there is adequate spare runway to accommodate the (possibly quite significant) ground run delta
(c) Vr is respected
(d) rotation rate is similar
then, for the same T/W, the speed at screen will be very similar for the V1 and V1- cases.