In vector v0.10, there are whole vector register load/store instructions. I suggest to use the whole register load/store instructions for generic load/store for scalable vector types. It could save up vset{i}vl{i} for these load/store.
For fractional LMUL, I keep to use vle{eew}.v/vse{eew}.v instructions to load/store partial vector registers.
Can we use MCRegisterInfo::getMatchingSuperReg to get do this conversion?