FL250. The problem with the Cirrus SR22T is that I cannot outclimb the weather if the top of clouds is above FL250. That said, climbing to FL250 to try to climb above the weather does not mean that in the climb you would be always in IMC. There could be layers of clouds, but ideally, I would want to climb on top. The top of clouds can be estimated from the GFS weather model, balloon data and the IR cloud-top temp satellite charts.
I would echo what ArcticChiller has said. I am still, after 40 years of flying, very careful about IMC into “unknown” cloud formations. I am also still amazed at the vertical limits of some systems after an unpleasant experience a long time ago. From those who fly regularly to greater altitudes than most of us, what is the “thickest” in height you have experienced before getting on top?
I didn’t get too much actual IMC during my IR training to effectively learn judging the clouds. I know my limitations and just won’t enter IMC if I am not sure about it, but a thread like this is very valuable to me. Just wanted to say thanks for this thread.
I would stay clear of A – D
E: the cloud edges are not sharp. Hard to judge from a picture, but would probably have no problem with it but would ask for 20 degrees to the left in order to avoid.
F: looks like the buildup is still developing. I would stay out and steer to the right a bit.
G: Looks like no problem assuming that I see light peeking through at the top of the picture.
H: no problem, but easy to avoid
I and J: no
K: probably I would have no problem with it. The “probably” comes from the mountains below it and if it has sharp cauliflower cloud edges (which it seems not to have).
L: I might fly through
M: Depends on what column of clouds is beneath it.
It is the ones you least expect that might get you.
E and G I would consider, none of the others.
Depends a bit on the stage of development. The same appearance of cloud can be bumpy as hell when building and relatively smooth when dissipating.
Lucius wrote:
Icing risk only true if temperatures close or below freezing.
I’ve seen icing from +4 to -15 OAT in clouds. OAT +4 in cloud means that it’s 6 or 7 outside the cloud and one could easily conclude that icing is not possible.
If you don’t want to over-simplify it, let’s say E, G and H are OK the rest I would avoid.
BTW Electrical activity shouldn’t be neglected. I’ve seen lightning strikes from such structures and event got one frying my winglets.
A is obviously no-go. B C D and I have a large shower dropping out of the bottom so are probably hazardous. E and F and H are ok (bumpy), and F where there is a gap is certainly OK (just don’t do it with anything bigger like a part of a CB, due to lightning risk). G is dodgy because you can’t see what is above it. J K L similarly risky due to being borderline CBs and thus lightning risk. M is OK though probably bumpy.
If you find yourself in these coulds, fly slowly, well below Va. It also makes it a lot more bearable for the passengers, who may not fly with you again 
Re: icing, you get a lot of it at the tops, even potentially at temperatures below -15C
