Longknile, if you cut the cone yourself you can have control over how much "grip" you leave at the muzzle.
Looking at your location, and being a fellow "southern boy" (I grew up and spent most of my life in Middle TN, just north of you), I'm going to take it for granted that you know what "sharp knife" means. If your knife is good and sharp, meaning you have had bare patches on one or the other of your forearms since you were 8 years old, you will not pop the load out of the muzzle.
I use a loading block with my coned guns (not all of them rifles) when using PRB. Using a thin block, the ball centers itself in the muzzle and I push it through with the ram rod, no short starter, flip the block off the rod when the ball is seated.
I shoot a lose patch ball combination in the field so this works well for me.
If you load from the pouch, use a very tight patch/ball, and have to fight the load down the tube, then coning will be of no benefit to you. You might as well use the short starter with a modern crowned muzzle.
Some folks have only one gun and do everything with it. I am not of that ilk. I have several and all of them have diferent uses. The coned muzzle guns I use for hunting (fast follow up shots) and for woods walks (where loading on the run/rapid loading are required).
At the target range, where time is not a factor, I want a tight patch/ball combo, and I will be using a short starter anyway, I don't care if the muzzle is coned or not.
If I only had one gun, it would be coned, just so I could have the benifit if I needed it.
:imo: