If you bomb the industry, you will need to fix the industry, and that costs a lot of supplies.
If I were in the situation, I would try to bomb the units (assuming you have good air superiority) to disrupt them, then when you think you have a favorable AV ratio, launch a shock attack with all units.
A few things to remember about land combat:
-Bombardments cause fatigue in your own units, so it is not always the best idea to bombard. Only use artillery units for full time bombardment.
-Combat uses supply. This applies to attacking and defending. Enough attacks will wear out the enemy in this situation.
-Shock attack adds strength to your attack(adjusted AV). It is true that you may take higher losses in case of a failed attack, but a deliberate attack has a lower chance of succeeding. That is why in most cases where I believe I have the advantage, I use shock attack. (I did not do this in old WITP, but I believe the routine has been changed significantly.)