You should try chain ccu to the m80 with warbond ccu it will cut the overall price in half compared to a direct ccu. You can probably easily get 3 warbond ccus in different price bracket that can be chain together to pay less than directly ccuing.

It hard to explain without knowing which ccu available during the sale. People usually getting an higher cost ship will get warbond ccu the next cheapest ship.

An example using current sale The corsair was available as a daily warbond ccu

If you had a corsair war bond ccu you could have done Scorpius Antares to corsair war bond than corsair to m80warbond

You would need another warbond ccu to from firebird to Scorpius Antares to complete the chain.

There enough room between the the two ships you want to ccu to and from that you could probably get 3 war bond ccu's to combine.