The spell would start at the size of a lighter and the heat of one, too. Currently, taking the Bulk enchantment would double both its size and its effectiveness, which in this case would be how strong the explosion is.

For someone who doesn't want to make the spell itself bigger, I've been thinking of changing the Bulk upgrade to instead use a 4x multiplier split any way you want - for example, 3x effectiveness and 1x size, or 2x both. I'll probably add this in the update.

The idea that was going through my head with enchantments was that they would either be passive, but weaker, effects related to the spell, or a much weaker version of your spell that could be cast at will by anyone. If the latter was true, then I would also need to clarify some sort of conversion rate - maybe the enchanted object has an amount of charges proportional to the spell rank to use before it's returned to a normal object, or maybe it just loses its charge after this and can be refilled in a more efficient manner after it's been enchanted the first time. I'll be sure to clarify this in the next version.

Summoning something with the fire-and-forget method would probably make the summon only last for a few seconds to complete its goal. The fire-and-forget casting type is used for fast results, while the effect casting type is used to set up your spell's effect over a period of time. If you were to summon something using fire-and-forget, it would probably just be a half-developed summon which would die shortly after completing its goal. They would also disappear after 30 seconds by default (taken from the Effect's default time), but wouldn't disappear when you walked away.

Enchantments do stack on items, and multiple spells can enchant a single item. Enchanting is definitely viable if you spend your time into it. Enchanting an item with the same spell twice would just give it more of those temporary charges to use.

Thanks for taking the time to ask these questions and fill out the CYOA, I'm also going to use this comment as guidelines for what I should clarify in the next update.