We have many similarities from boat size, usage patterns, boat age, engine etc. Having gone through the process of upgrading basically everything on my boat I can give you my thoughts/justification. In general, my decisions were value based.
Batteries - I was very torn on this, waited in the Firefly order queue for 6+ months and finally my turn was up... I ended up passing on Firefly’s and went with 3x East Penn (Napa) g31 gel batteries. Just installed them last weekend, too soon to know if this as the right decision. For me this ended up being a value play, boat is a seasonal use (Lake Superior) and sits in the hard for half the year. 3x Firefly’s were close to $1700, the East Pen gel were $740 or so for the 3x. I know I technically could have gone with 2x Firefly’s but the weight saving is not a huge deal to me as I’m mostly a cruiser. Rod and Bruce Schwab Have nothing but positive things to say about gel’s so long as you charge them right, fingers crossed!
Alternator - I went with Rod’s CMI-80 and a Balmar MC-614. Again, price to performance play. I have it belt managed to level 3 (15%) and on the old batteries (3x East Penn AGM (West Marine)) saw ~62 or so amps out of the alternator last year. Again I hemmed and hawed over a Balmar alternator or Mark Grasser but for the extra maybe 20 amps only during the short period the batteries can accept the high current it just didn’t make sense. Old alt was stock 60amp Hatitchi which put out maybe 20 amps at most. Got all the temp sensors and wired direct voltage sensing wire per Rod’s install guide. I really want a serpentine belt conversion kit but that’s silly for my size and use setup, I went from no belt dust to some so I need to figure that out.
Solar- I did 2x 100w flexible panels (Chinese ones) on the Bimini with a Morningstar SunSaver controller. I picked that controller as it was the the only one with every option possible in this size range- temp sensor, fully controllable and I forget the other reasons. I likely slightly overbought on the controller but my boats name is also Morningstar so...

. Rod would cringe at the actual output vs. rated on these panels, but at 20% the cost of Solbian it works for me. My usage is actually only in the 60-80 amp hours/day so only getting 6-8 amps out of the panels is ok. Plus the long days up here help up the amp hour count.
Shorepower charger - Promariner 40amp. Seemed like a no brainer, temp sensors installed with custom charge settings.
Anyways, that’s what I did. Too soon to know how well it all works. I really wanted Firefly’s but for a weekender/seasonal use boat with a few week long trips I just could not justify it. Part of me thinks in a few years I could just jump to Li depending on how long I keep this boat.
Ps put LED bulbs everywhere! Huge reduction in my electrical budget.