I find the Sha Yu 2B quite usable. Stealth on, go to attack range (whatever your pilot's comfortable with i suppose), fire a turn or two, run away to cool down, repeat. Tricky, to be sure, and few infernos can ruin your day but Capellans live on the edge always...
Alternatively one might use stealth while going for a good firing spot, turn stealth off and attack, turn stealth back on and run away.
The 4B is certainly simpler to use. Get in close, turn stealth off, attack AND spot for C3 network (if you have one). The LRM is useful for, say, laying smoke screens or mines (assuming advanced rules in play, of course).
The 6B is the weird one for me. While the snubbies have nice short range, stealth would be useful at range 9 against many weapons.
EDIT Pity the 'Mech doesn't have mass for MASC, would've love it on the Sha Yu. EDIT actually, with some tweaks it might be possible...