If the only difference is temperature then any shelter is fine. If you’re also dealing with more unsettled winter weather that comes with higher winds, the heavier / stronger Dyneema in an Ultamid could be the difference between your shelter surviving a night or not.
On the other hand, if you are going out in snow then you are playing a different game entirely. You’ll probably need to pitch the shelter with walls touching or slightly buried in the snow to avoid spindrift. That will complicate ventilation which means condensation is likely a bigger problem which means you really want plenty of space between you and your sleep system and the walls of the tarp. And if snow is falling or being driven around by the wind it’s pretty unpleasant to cook outside so having plenty of ‘vestibule’ space is well worth an extra oz or two.
I do a lot of multi-day ski touring and for shelters without a vestibule in snow I always want it to have a ‘summer size’ of twice as many people as will actually use it. For 2 people in snow I really like an Ultamid 4, only 3.3oz heavier than an Ultamid 2 and plenty of space for 2 people to sleep without touching walls and store gear and cook. For solo trips I use an MLD Duomid which is made from a similarly burly Dyneema to the Ultamid but is slightly smaller than the Ultamid 2 (though still larger than the Mid 1). The slightly smaller Duomid saves 3oz over the Ultamid 2 but I wouldn’t want to go any smaller for snow camping.
The easiest way to save some weight with the Ultamid 2 would be to ditch the dedicated pole and buy a ski strap that lets you connect 2 trekking / ski poles together to be long enough to pitch the Ultamid.