Gold guinea has slightly less brokerage than Gold Mini. At 0.03% brokerage, it costs me Rs ~6 each way for one lot of Gold Guinea and Rs ~80 for one lot of Gold Mini each way when the same cost in Gold Guinea is Rs ~60. 10 lots of Gold Guinea brings the same benefits as 1 lot of Gold Mini (1 rs rise in price of gold = 10 Rs profit when going long.)
One reason that I may trade in Gold Mini instead of Gold guinea (despite gold mini's overall higher security deposit and brokerage) is that the risk of slippage increases when more than 4-5 lots of guinea are traded in one market order.
Traders with less than 1 Lakh capital may prefer trading Gold Guinea over Gold Mini. With Rs 10,000 capital, adding one gold guinea lot (or gold mini lot if starting capital is 1 Lakh) for every 100 Rs rise in the price of gold can lead to a very healthy accumulation of guinea lots.