10540
I would be very cautious of taking off where the temperatures meant any ice I picked up I would hold to the ground.
That is especially true of low powered non deice/anti ice piston singles.
It is hard to determine tops and whther those tops 40 miles down road dont go up.
My best friend a ferry pilot was killed in such an aircraft believing he could get between layers and out of icing.
Its ok picking up ice if you know that dropping to MSA will see the lot melt off.
With any IFR/IMC flying the pilot has to be up to the job but being up to the job means knowing and respecting the limitations of his aircraft.
If both pilot and aircraft are up to the job thats another matter.
Usually icing to the ground and fog are the two states which concern me and I fly all year in almost anything but the smallest aircraft I fly are deiced anti iced turbo Seneca 5s.
I would be very cautious in anything serious if its a single piston.
I do know what you are getting at but just add that word of cautious for our newer less experienced IMCR pilots.
Pace