That depends on the person, really. Some gymnasts have smooth, aligned BHSs with good flexibility and don't seem to struggle much with working out of the faster first skill, but they may have problems achieving the amplitude for the salto.
Others may really struggle to move from a slower connection to a faster first skill (particularly if they aren't used to an aggressive sit and swing to initiate beam BHS), but don't have much trouble making the layout, and don't find it that different.
I never consistently did BHS BHS. I half heartedly did various progressions for it during basics as required, but I basically moved from doing a BWO BT (learned BWO BHS first though) to doing BHS BT and BHS two foot layout. I have no idea what would go down if I was a level 8 today, because I'm pretty sure I could not competently do any of the currently allowable series consistently. Since I generally struggled with any alignment on beam, it didn't really seem to matter, and my ridiculous falls actually ended up less painful from the position I missed saltos out of vs the positions I missed BHSs out of.
Some girls don't physically struggle with making any of the series look smooth and consistently landed (though they may have fear issues). Overall as a general statement I'd say working on that first BHS is pretty key...it's harder to align than the BWO for many and no matter what you're doing out of it, it takes awhile to learn how to push through a punching connection.
