You probably will find that the result will be simply to push the tractor sideways as a lot of front weight is needed.
Damage to the front wheels or rims might occur. (I trashed mine that way)
The safest would be to occasionally attack the banks at an angle every 8-10 ft or so, OK, slow but safe and probably only once or twice per winter. And doing so with front wheels not angled.
I once made an extension like you propose on my heavy plow truck and it resulted in a few shattered front right axel shafts and Ujoints.
Now on a heavy tractor (like 60-100 hp) that would not be a problem.
In fact with my 20 hp CUT I tackle snow banks every so often always now 'straight on' a couple time a season.
Best time is whenever there is mild day or better a brief thaw as then the snow banks are soft and easy to push back.
Even our road contractor attacks the snow banks with his tractors and loaders whenever we get a mild break as he simply needs the room to push next snow events.
We get , like 100-200 inches around here.
LOL, my worst event when I truck plowed was a 34" dumping in one day. I almost cried as my blade was only 24" high and all my drives were downhill towards lakeside and most were long.
Easy going downhill but would I get back up?