I think you’re still confused, if I understand what you’re saying.
Wait for Krieghund. We need his answer on the bombed out base question anyway, right?
If you have a tac and strat bomber(s) going at the same base and you take an AA hit, you can always lose the tac. A bomber of the attacker’s choice is removed.
It’s during the air battle that you have all the fighters, tacs, and strats together rolling 1’s to attack interceptors, and are being fired at by interceptors. You can take off fighters, then tacs if you want for interceptor hits. After the air battle, you divide your tacs and strats into groups. Each facility fires at the group attacking it. Attacker can remove tacs first in the case of attacking a base with a mixed group (otherwise, there really is no choice because it’s only tacs, or only strats).
Your question seemed to be, can you take in tacs to shield your strats from interceptors even when there is no base (answer is “no”), or if there is a base or 2 but they are fully damaged so can’t take any more damage (not sure, need Krieghund).
Your tacs can always shield your strats from AA fire at a base, IF you are taking in both tac(s) and strat(s).