??? Fuse UpGrade??What Size???

Let it burn in for a week and then switch the direction. If it wasn't in the optimal direction, you should hear a very noticeable difference. If it gets worse, well switch it back. I tend to oversize the fuse... thicker wire. 

Go with a 6 amp fuse Fast blow. SR fuses had a history of blowing on inrush current startup if you went with factory size. 

The Cable Company has them on sale.  

I would call SimAudio (Moon) tech support to get their opinion/advice.  I've received helpful advice from them on my Moon 390 set-up.

One is 20 mm ,one is 32 mm, you can see if it looks small or longer

and if fast blow always go 1 size up I have had fuses go in fast blow fuses on startup why ? The cheap stock fuses can vary up to 20%  

I recently upgraded my fuses for my Shindo Mr T,Aqua LinQ transporter and Weiss 501 MK2 for the Pink fuses and after experimenting with the right direction and between 100-200 burn in time,I can hear a very noticeable difference with the soundstage(,wider and higher),Instrments and voices are more detailed and airy and the overall sound is more live. I also recently bought a Rel S510 sub and Wow! It was probably my biggest upgrade. I know adding a second sub would complete the 20% on the 80 % upgrade but I live in a condo with neighbours downstairs so 1 is satisfying for me, should have done this years ago.