Some brands and models of cells prefer a fast charge, some a slow one. Do you know the brand and model of your cells?
It really has next to nothing to do with how many cells are in your parallel groups, which is what makes "Amp-HOURS", which are very different from just "Amps".
You have a two-amp charger because they are less expensive that higher amp chargers and the one you have was included with the battery.
Yes, you can get sparks, you can also eliminate them with anti-spark connectors.
You want a recommendation, of a good brand, of Chinese-made charger? Please do some research so you can share in how hilariously funny this question is.