2) I connected to someone's node (because I do not know how to create one) that has an average ping time of 75 ms, is this good?
75 ms is fine. The network latency to the node is a lot less important than the CPU speed of the node. A node with a slow CPU might take 3000 ms to hand out new work to your workers, whereas a node with a fast CPU might only take 500 ms. Whether you're adding 1 ms or 200 ms of network latency to that is nearly (but not quite) irrelevant.
looking at the nodes' scanner page, is there anything can tell us about CPU speed of a node?