check this site...
http://www.russianammo.org/Russian_Ammunition_Page_25mm.html#8
might give you an Idea.
also this is the arms dat
Nudelman-Suranov NS-23 23mm Cannon (1945),1,-99,2,0.11,690,2,0.05,400,4,40,1d1*38,0,0,0,0,0,0,0,0,0,0,7.05,Soviet Union
Nudelman-Suranov NS-23 23mm Cannon (1945),1,-99,2,0.1,690,2,0.05,400,4,40,1d1*32,0,0,0,0,0,0,0,0,0,0,6.6,Soviet Union
SchWAK 20mm Cannon (1937),1,-99,2,0.08,830,2,0.05,500,4,99,1d1*31,0,0,0,0,0,0,0,0,0,0,3.39,Soviet Union
Vja 23mm Cannon (1941),1,-99,2,0.1,900,2,0.05,500,4,40,1d1*33,0,0,0,0,0,0,0,0,0,0,7.05,Soviet Union
AM-23 23mm Cannon (1954),1,-99,2,0.05,690,2,0.04,400,4,40,1d1*38,0,0,0,0,0,0,0,0,0,0,6.61,Soviet Union
B-20 20mm Cannon (1944),1,-99,2,0.08,800,2,0.05,400,4,40,1d1*28,0,0,0,0,0,0,0,0,0,0,3.39,Soviet Union
GP-9 23mm Cannon-zwilling (ca. 1965),1,-99,2,0.03,1000,2,0.06,500,4,40,1d1*39,0,0,0,0,0,0,0,0,0,0,7.05,Soviet Union
GSh-2-23 23mm Cannon (ca. 1965),1,-99,2,0.02,740,2,0.06,400,4,40,1d1*45,0,0,0,0,0,0,0,0,0,0,6.17,Soviet Union
GSh-23L 23mm Cannon (ca. 1965),1,-99,2,0.02,740,2,0.06,400,4,40,1d1*45,0,0,0,0,0,0,0,0,0,0,6.17,Soviet Union
GSh-6-23 23mm Cannon (ca. 1965),1,-99,2,0.01,740,2,0.06,400,4,40,1d1*45,0,0,0,0,0,0,0,0,0,0,6.17,Soviet Union
Nudelman-Richter NR-23 23mm Cannon (1949),1,-99,2,0.07,690,2,0.05,400,4,40,1d1*38,0,0,0,0,0,0,0,0,0,0,7.05,Soviet Union
that is everything for 20mm and 23mm. so you can see why I chose the value that I did.
on to the fuel...
Here is what I calculated. it might not be correct...
All in gallons;
Total=290.59 - LA-11's total fuel load
MainOnly=217.94 -original LA-9
Wing Tanks=72.65 - the extra added
from that this is what I came up with.
again all gallons;
Wing tank1=39.325
Wing tank2=39.325
Main1=130.764
Main2=87.176
Now I used the LA-9 as my starting point. then just did the math.
I'll send what I have.