I don't think you have your trim specs right.
Trims are usually whole numbers. The 74.2 just so happens to be the measure of one particular turbo e wheel's inducer diameter - and it is for a GT3076 turbo.
A 50 trim compressor section is one of the just right compressors for our size engines in the normal journal T3/T4 series turbos.
If you want lower spool the the T350 turbine (stage III) would be perfect. If you want more top end power then go with a stage V turbine.