The following buffers are recommended and proven for good I.I. results.

If anyone in UK is interested I can offer these ready made for sale

Hyes Solution

0.9g Sodium Chloride
0.2g Calcium Chloride
0.2g Potassium Chloride
0.1g Sodium Hygrogen Carbonate
Deionized distilled water to 100ml
Adjust to pH 8.5, autoclave, aliquot, store -20C

Verma Tris buffer

0.61g 50mM Tris pH 8.7
1.1g Soduim Chloride
0.1g Glucose
0.01g L- Arginine
0.01g L- Lysine
Deionized distilled water to 100ml
Adjust pH 8.8, Filter sterilize, aliquot and store -20C

Varhom Kiev

0.3g D-Glucose
2.43g tri-Sodium Citrate
0.21g Soduim Hydrogen Carbonate
0.3g Sulphanilamide (anti bacterial agent)
Deionized distilled water to 100ml
Adjust pH to 8.7, Filter sterilize, aliquot and store -20C

Antibiotics

Stock solution 10,000U/ml store in aliquots at -20 C. If desired add antibiotics Penicillin and Streptomycin before use to a final concentration of 100U/ml (ie 1/100 dilution - 200ul per 20mls buffer)