Thank you for posting
When we sit in a game for the first time we cannot know we have an edge on the table nor how the table plays as a whole. Under those circumstances we should buy-in short stacked and top up as soon as we know how the table plays. If the min buy-in is 40bb or more then we should buy-in at 60bb as 40bb is to high for true short stack poker strat.
We of course need to know how to play short stack poker. If not 60bb buy-in top up to 100bb if you have position on the weaker players if not stay at 60bb if the better players are on your left.
You want to ask what a min top up is. Some casinos only let us top up once for less than the table min often 40BB is the min buy-in. We do not want our stack to fall below 60bb's for any length of time as it is -EV to have a short stack when that big hand comes along.
The key to live poker is: table selection and then seat selection. Always move to the table that is having fun and always move seats if it gives you better position in relation to skill of villains.
Hope this helps