Manual J – done using coolcalc, verified using https://betterbuiltnw.com/
Manual S – done using Fujitsu slim duct, I have been looking at this model # https://hvacdirect.com/fujitsu-12-000-btu-20-seer-ducted-mini-split-heat-pump-system-12rlfcd.html

Selected equipment is 0.36ESP and 383CFM, installed in the upright position not in the “concealed ceiling” configuration. Drawing of floor plans and proposed duct layout attached as well. Ductwork in the attic (western NJ, R8 duct insulation), this is the only place it fits and I covered this in another post. I have not done Manual T yet and just kinda guessed on register locations for now. So first question, does anyone have links to resources on Manual T? I couldn’t find any free versions of Manual T online.

The following questions are regarding my Manual D and equipment features. Also looking for general input and feedback on my design. I’ll be permitting and installing this myself.
1. I tried to choose low loss fittings that I have seen before in HD and online and won’t have to hunt for. Once I had a rough TEL set up I then corrected the fitting ELs for the max velocity in my ductwork and design friction rate. This was a bit iterative and I finally honed in on about 600FPM max and 0.08. Is this methodology right and do my velocities and sizes look good?
2. I would like to use a nice filter and not the 1″ cheap ones. In order to keep velocities low and also losses low I need a deep and pretty large filter. I’ve been unable to find any deep filter grilles online anywhere, can anyone point me to some? Also looking for guidance on how to properly size the filter grille. It will need to fit between a joist bay @16″OC. My design loss for the filter is currently 0.1, based on my research I think this is achievable with a low enough face velocity.
3. Does the Fujitsu slim duct have any insulation built in or should I plan on building a very large foamboard housing to fit around it?
4. Do I need to be worried that this unit doesn’t have a base pan heater. My design heating temp is 5F?
5. The design and engineering manual makes lots of reference to using aux heat, I just want to confirm that this is optional and the unit will run fine down to -5F as advertised without aux heat? I have a pellet stove and electric baseboard as a backup.