Well, one piece of information is that your Bryston 28B amps do not use fuses. They use circuit breakers instead. So you don’t have to worry about those pieces.
As far as testing the waters, I would probably start with your ARC LS 27. It looks like it uses a 3A fuse and it appears (based on the pics) that it uses the large 6.3mm x 32mm size fuse. You don’t have to burn in the fuse on the ARC. You can use an alternate device, such as maybe your MAC CD player? (as long as the physical size is the same). A 3A fuse is somewhat larger that I would put in a solid-state source device, but you could run it in for 10 days before placing it in the ARC. If you liked the results, you can try in your RIAA phono stage and your CD Player or MEN220. For fuse burn-in, you do not have to play audio through the device. You just have to make sure the device is powered on.
For fuse selection, we all have our preferences. I personally do not like silver based fuses (Hi-Fi Tuning, Synergistic SR20) because they have a push in the upper mids and sound artificial to me. They very fast and detailed, though. I think the silver does not have the ultra-high frequency “air” that the Furutech fuses have (I think silver actually rolls off the very high frequencies somewhat, we are talking like above 14khz or so). I have read that ARC is very high resolution and resolving for tube gear, so Hi-Fi Tuning or SR20 may not necessarily be the right choice. It highly depends on personal preference. There are some who like Hi-Fi Tuning better than Furutech.
There was one user who put a Furutech in his tube amp and had improved sonics. When he replaced the Furutech with a BLUE fuse, he did not hear any difference. This could be limited resolution from the tube amp. Others that have upgraded from Furutech to BLUE indicate a good improvement in sonic quality. Others indicate that BLUE may tend to roll-off high frequencies in comparison to BLACK. However, this could also be that BLACK fuses are very sharp in the high frequency detail. I have not tested BLUE or BLACK personally, so I could not be sure. The BLUE/BLACK are definitely a lot more expensive than Furutech, but they have a 30-day return guarantee..
One thought I had was to ask how attached you are to the MEN220. A quote from the following link:
https://www.audioaficionado.org/showthread.php?t=5072&highlight=MEN220+Review&page=31
I thought it might be of interest to some. I scrutinized the service manual for the men220. The analog inputs are digitized by a single akm ak5394a analog to digital converter(adc). This is a 24bit/192khz delta sigma adc, sn/dr of about 123db. There is a separate adc for the microphone input(akm as well). Then the signal is processed (room correct) in 2 Texas Instruments audio dsp, there is also an altera fpga in there. As a final step, the signal is converted back to analog via 2 wolfson/cirrus logic dacs, one per channel. These are 24bit 192khz dacs with about 120db sn/dr ratio in differential mono mode.
Since it is a digital signal processor (DSP), it is required to convert the analog signal to digital before doing the equalization/crossover. Then it converts back to analog via a DAC chip. You will lose some of the original analogue sonic signature doing this. Have you ever thought about removing the MEN220 from the signal chain and see how it sounds? If you have an environment which absolutely requires room correction, maybe this isn’t a good idea. Just a thought.