100% of the Locker’s voting rights (Angle Protocol governance + gauge allocation on Angle protocol) remain for sdANGLE stakers.
Indeed as you identified, some sdANGLE will not be in the sdANGLE staking contract but in the Curve factory pool (ANGLE/sdANGLE), the veANGLE voting right represented by staked sdANGLE will therefore be strictly superior to 1.
As a baseline on average, 1sdANGLE vote > 1 veANGLE vote as users stake into the Curve Factory pool to capture incentives (SDT, possibly CRV).
On top of this, but on top of this, voting right will be boosted by the number of veSDT held by each user (same boost formula as the veANGLE boost one).
In a very extreme case, if a sdANGLE staker has no veSDT while all other stakers benefit from maximum boost (max veSDT locked), and Curve factory pool has nearly 0 liquidity, the minimum vote held by this sdANGLE staker would be > 0.4 veANGLE.
This is a very extreme case, and is already much better than any other existing lockers. On average the simulations show people with no veSDT to have around 0.8 veANGLE voting right while people with max veSDT boost will have more than 2.5 veANGLE vote per sdANGLE staked.