Global Ritual Questions

[Velusion]

Some late game global ritual questions:

1. I heard that the most gems you can ever put into a global is 999 - is that true? Does that include the base cost of the spell?

2. I know ritual casting sites (e.g. Conjuration 20) discount the initial ritual spell cost - do they have any effect on the extra gems spent to boost the power of the spell?

3. When casting global spells I know each level above the minimum boosts the strength of the spell by 5. Do magic boosting items you are wearing affect this - or does it only look at your innate ability in the magic path?

Any help ASAP would be greatly apperciated!