Willy,
Both roundballs & Ballets shoot better at 100 yards in my 1-70" twist T/C Renegade and my 1-66" twist Traditions Shenandoah than they do in my 1-48" twist rifles. The models you picked out are all 1-48" which shoot medium & heavier-weight conicals well -- but a majority of 48s only shoot roundballs & ballets well 50-75 yards. So you need to find out how far your shots are going to be.
The Lyman Deerhunter has always been one of my favorite sidelocks in the $210 range. It also shoots a variety of sabot/bullets well too... which the 1-66" twist won't. Here's a link for the optional 1-66" I suggested you consider also.
Tradtions Kentucky Long Rifle 1-66" twist