I have a second account and I did the LS collection for Mantle last week and it immediately got me Trout when I was done. I did have many cards built up - legends, finest, etc. - but LS made Trout a breeze.
Mantle from almost scratch - no LS Diamonds and very few gold's locked in - cost about 500-700k (the show zone might have an exact number.) I made back about 90k. Once I locked everything in for Mantle, Trout ended up being an afterthought and the easiest collection ever.