Pookee,
Since you were asking for the best choice, and you mentioned the T/C and the Ruger Redhawk, you have already made the right choice by going with the T/C. As to what caliber, I'll let you know how I settled on my choices. I was shooting the Field Pistol game at the start with a 22lr or sometimes with a borrowed .357. I asked around and settled on the 32 H&R Magnum in a T/C. I was using this with a detachable scope mount and was doing quite well with it, shooting a 75/80 FP agg. Due to helping out another shooter and a strange twist in the production rules, which has since been changed, I was led to obtain another barrel for PAS. I borrowed a 22Hornet barrel from a friend of mine and headed to the INTS in 2001. In PAS, the little hornet rang the last ram, but I still won by seven targets. I ordered a barrel in 25-20, as that was the in-thing at the time and I do not like to 'miss' targets that I hit, but never did take a liking to it. I could never get my confidence level up with that barrel as I had with the 32 Mag and that 22 Hornet barrel. Last year I sold the 25-20 barrel and bought my friends 22 hornet barrel (for the history), and now shoot the 32 Mag in Production, (I will never sell this barrel, nor shoot anything else in a Field Pistol Production match that I wish to win). I have shot a Ruger SBH 44 mag with 10 1/2" barrel and a Colt Mustang 380 with a 3" barrel, but just for fun. I have shot three championships with this 22 Hornet barrel, and have won each with impressive scores. To date, I have not shot better than a 38 PAS with the Hornet, but I was also shooting 38s with the 32 Mag in PAS. The open sight 32 mag routinely gives me 36s and 37s, and once even rewarded me with a 39, never ringing a target.
Larry H