Is there a noticeable difference between the 5.4 and 5.0? I have a 5.4 coming and I just had to bite the bullet. I couldn't test fire a 5.4 here in Australia because there are none!
I am currently using Vihtavuori 3N38 in my SVI but I am using Berrys projectiles.
Depending on where you are it may be hard to find any 3N38, I know there are some shops selling 500gm bottles around the $72 mark.
357 Sig is very popular over here in Australia as we cannot shoot 40.
A lot of people are using heavier projectiles for IPSC Major power factor.
I use a 170gn round nose with 5.3gn of AP70 (Universal Clays in the USA) loaded to 1.25" in an STI.
I have only tried Berrys 124gn RN with 10.0gn of 3n38 in my SVI IMM and they are pretty good.
Have a box of Xtreme 125n RNFP that I'm yet to try.
Shoot under IPSC rules so no 115gn
Living in a country where a 5.4" limited gun is as rare as a unicorn, I am interested to know the difference and advantages of the 5.4" over the 5" for IPSC Standard division.