Just adressing this; using actual magic bullets is against the spellcard rules. It's the spellcard rules which limit your 'nonspells'. [A nonspell can't be stronger than a spell in the spellcard rules]
You can use your full power whenever if you're not going to follow the rules. It *will* drain you faster since obviously it's easier to create dummy bullets than ones that can kill youkai and such, but it won't make your patterns weaker. There are exceptions in energy consumption; such as weapon-based attacks that use less energy outside of the spellcard rules because you're not materializing anything... you're just attacking with your weapon. It's easier for Sakuya to throw real knives than make phantom ones and throw those.
Also danmaku dosen't do friendly fire. [See: Primsrivers; Toyosatomimi; and other team fights; even the fighting games like Kokoro's final boss fight in HM] So you wont need to worry about Sakuya. Real attacks do friendly fire.
// Thanks for the reminder
! //
// Well,this could make Elis stumble a little seeing she do not know it first-hand,unless she has experienced it while facing off Sakuya+Remilia , that it is a "defensive bridge cover",without over-estimating it, going to Rumia to Sakuya and back; such a "defensive bridge" could be an outreach for any danmaku in an useful position by Sakuya to Rumia as well .//
// Seeing as Rumia cannot (yet?
) upgrade to Impossble Spell Card , I am inclined to suggest a little inquiry before going ahead with the Final,or next-to-Final, Act :ohdear: //
> When not using spellcards,do we have a trade-off in a significant boost in mobility,reaction time and more readiness in projecting barriers?
> Would that specific denser pattern of "(Fake) Midnight Bird " build some cover and mobility for Sakuya and us with the respective range of all 3 involved?
> Do not proceed,not yet,if the responses are negative.
> If instead it is truthful go as planned(Tom's)by track both Elis with a very dense pattern of "(Fake) Midnight Bird" while allowing both us and Sakuya to use it as a cover and additional mobility,besides the ones granted by not using Spellcards,especially so as an obstacle for her whenever she gets to get too close or have a good aim on Sakuya or even us.