Most tax efficient means of releasing shares

Hello

I have a number of shares vesting from a couple of employer-related schemes, one a Save As You Earn and the other a deferred bonus scheme.

If I’ve understood correctly, the most tax efficient means of releasing the money (should I choose to sell the shares), is either to:
- put into SIPP
- transfer into ISA.

Is this correct?
I am likely going to make a payment into my SIPP before April 5 anyway so this may be the best option but trying to understand each one.

If I transfer into ISA do the shares then transfer to cash, I think I would prefer to sell them rather than hold the risk of the share price?

Finally, if I transfer them to my husband instead can he then sell them without incurring tax or just within the CGT allowance for the year?

Thanks so much for any guidance!