Questions regarding usage

[m1u0]

I have a few questions about the usage of NamiColor. For reference, I am camera scanning with a macro lens.

1. Channel alignment: Is it optimal to use the unexposed/fully exposed portions of film as the black/white point? I would do this by scanning the film leader and an unexposed portion outside the frames and adjusting the per-channel shift/gain until those are at 0/1. Then, I would apply the same settings to all other scans. I see no problem with using the unexposed portion as a black point, but perhaps the ratio of 'clipping points' for each color layer in the film is different from the intended response at normal brightness levels.

2. I am converting from Fujifilm RAF to TIFF in RawTherapee. I leave almost everything to default (WB set in-camera), except color management output profile to a custom profile (made in the 'ICC Profile Creator') with ProPhoto primaries, linear tone response, D65, and ICC v4. Will this result in a scene linear image?

3. I am currently exporting the TIFF in 16 bit float. My raw files are 14 bit; can I use 16 bit integer for the same (maximum) quality? Or is 32 bit float even better? (I don't really know how color bit depth works)

4. I use an OLED screen as the backlight for my film scanning setup. In an attempt to get the best per-channel SNR, I adjusted my screen to a cyan color that makes the film base approximately white. Then, I adjust shutter speed until the film base is almost clipping. Will this result in different final colors than using a white light?

I have tried the above process and it gives good results, but I just wanted to check if I could make any improvements. Ideally, I would like to arrive as close to as a motion picture lab scan as possible.