Excellent choice — #3 of 31 Angora ranks #3 of 31 fabrics for warmth without weight. It is one of the best fabrics for this. Ranked on warmth relative to weight, with a packability bonus. The top pick is Cashmere.
Angora measures 45/100 for breathability, 14% moisture regain, 92/100 warmth, at 240 gsm. Warmth-to-weight is the metric: 92/100 warmth at 240 gsm is an excellent ratio for packable insulation.