A question regarding HHM funds rank

[dondon151]

Right now I'm at chapter 24 (soon to be 25), and I have a plethora of lv 14-18 unpromoted units sitting around because I've been using a larger group of units to stay ahead of the 5-star experience requirements.

Prior to the chapter I decided to see if promoting one of my units would have an impact on my funds rank, and apparently the loss of 10000 G in funds would drop the funds rank from 5 stars to 4 stars. Now, I know that I can't possibly afford to promote all of my 10 or so unpromoted units (not counting lords or thieves), but how many should I expect to promote so that I would still retain 5 stars in funds? And by extension, how necessary is it to use prepromoted units late-game in an HHM S-rank run?

Also, should I promote Eliwood and/or Lyn? I've read somewhere that the two non-Hector lords usually go unpromoted in HHM ranked runs in order to preserve funds, and since the Heaven Seal is worth 20000 G, I could be promoting four other units instead of Eliwood and Lyn. However, I'm a little worried about their survivability in later chapters for which they are required.

I'm assuming that I also shouldn't recruit Farina? I've been using both Florina and Fiora, and while having the utility of 3 Pegasus Knights is nice, Farina requires a 40000 G investment (in my current state) in order to make her useful. Not to mention, Florina and Fiora are both turning out great this run-through.

[bonestorm99]

Your funds rank does NOT go up by selling stuff. I sold an
ocean seal and got 50000g, but my funds rank went down right after

[dondon151]

Right, I know that. Selling an item cuts the return in half; this is why i said Farina would be a 40000 G investment because it's 20000 G to hire her, 10000 G for the Elysian Whip, and 10000 G for selling the White Gem that I need to get the 20000 G to hire her.

Another question: since chapter 25 has 0 requirements, what's generally a good turn count to complete it on HHM?