How would you implement Smoke Shells on SPGs?

I haven't played WoT in a long while, and while I know that some tanks were given Smoke Screens as a consumable, SPGs were not among those who got them (AFAIK). In Company of Heroes 2, though, some mobile artillery units in that game can fire smoke shells to obscure vision.

This got me wondering how smoke shells could be given to SPGs in World of Tanks. I have a few thoughts on it, but consider it a rough draft.

• Each SPG receives Smoke Shells independently of their ammo count for other shells. For example, the S-51 with its 203mm B-4 gun would still get 12 shells of either HE, AP, etc., but would also get 3 Smoke Shells (15 shells total). The addition of Smoke Shells is automatic and does not decrease your number of regular shots. Smoke Shell resupply does have a cost, but they tend to be very cheap.

• The number of Smoke Shells an SPG gets is fixed based on the gun it is using; you cannot sacrifice some HE/AP/etc. shells to carry more Smoke Shells.

• Smoke Shells must be manually loaded during a match, which takes the same time as loading any other shell.

• When fired, a Smoke Shell will create a large cloud of smoke on impact. The duration of the smoke and its radius vary per SPG and gun used. The smoke obscures LoS in the same manner that Smoke Screens do on other tanks.

• Smoke Shells do no damage if they hit an enemy tank, but may cause some detrimental effect to the enemy tank's crew. However, players should be discouraged from firing Smoke Shells directly at the enemy.

• SPGs who provide good smoke cover for their allies should be able to receive bonuses in credits and experience.

Does this seem like a good starting point? I know some people probably wouldn't care for it, or some might say that it'd go against what those SPGs could carry in real life, but it's at least worth thinking about. SPGs are supposed to be the "support" role, and being able to drop a big cloud of smoke down in front of your teammates could be very useful.