if you have problems mixing the extra 3g of metol you can mix up an extra 50ml with a pinch of sod. sulfite and add it to your 500ml. remember to account for the extra 50ml your A solution which will be 550ml. i've experimented with metol/sod. sulfite A baths and have found that there is a big difference between 6.25g/Litre and 7.5g/Litre solutions - the latter being more sensitive to temperature variations as an A bath ( B bath being 20g/Litre of sod. carbonate ). i imagine 8g of metol to be quite active and require repeatable temp control. good luck with your experiment and let us know what happens. i'll be very interested.