[Japanese > English] 大体 vs 目安 as an app name — and does "Daitai" in romaji risk reading as 大腿?

I'm naming a small personal health-tracking app (meals, weight, steps) and I'm stuck between two Japanese words. I don't speak Japanese, so I'd rather ask than guess.

The app deliberately doesn't pretend its numbers are exact — you can weigh your food to the gram, or just describe what you ate and let it estimate. So I was drawn to words around "approximate" rather than words around "precise".

The two candidates:  - 大体 (daitai) — "roughly, approximately"  - 目安 (meyasu) — "a rough guide, a benchmark to aim at"

Three things I can't judge for myself:

1. Written in romaji as "Daitai", with no kanji, in a body/fitness context — is 大腿 (thigh) a plausible reading? Or does 大体 dominate strongly enough that it wouldn't occur to anyone? 2. Do either of these read oddly as a standalone name? In English, calling a product "Roughly" would be mildly witty, while calling it "Guideline" would be flat. Where do these two land? 3. Does anyone actually perceive 体 ("body") inside 大体, or is the compound opaque, the way English speakers don't hear "break" + "fast" in "breakfast"? The app tracks body metrics, so I genuinely don't know whether that's a real resonance or one I've invented.