[DS] Smaller and larger HAR's

Okay, I have now 3 sizes of HAR looking vehicles - Stan Johansen  for
the 
smaller HAR's, some GZG wheeled (USSR?) vehicles for 'standard' HAR's 
and some 
plastic "Ebay Specials" that look like they may be 10 (to maybe 15) mm 
scale 
larger HAR's.
 
Anyone done variant rules for different size HAR's?   "Standard" HAR's
are 
'Heavy Artillery' so the smaller HAR's could count as  'Medium
Artillery' but 
how to handle the larger HAR's?  Maybe 'Extra Heavy  Artillery'?  Maybe
limit 
them to one type of Artillery Ammunition per  battery?	Or one of each? 
Perhaps 
the weapon class = 8?  That  would require they basically fill (at {8 x
3} 
with one capacity point left over)  a class 5 vehicle.	An alternative
would be 
size class 7 then there would  be room for some other systems.	I like
the 
Class 8 idea  myself.
 
Costing for the weapon?  I have no idea but maybe 300 or 400  points for
the 
Extra Heavy Artillery since the progression is 50-100-200 for  
Light-Medium-Heavy?
 
Gracias,

Glenn  "warbeads"