I own a Tauras Raging Bull in 454. I have also shot a Rugar Super Red Hawk in 454, a S&W 500 and a Tauras 500. I further own a Rugar Super Black Hawk in 44 Mag. Both Tauras' are factory equiped and are very comfortable to shoot. The Red hawk was absolutly horrorable. The original graps did not fill my hand and it was not ported. The grips stung my hand so bad that it was numb after only three shots and the muzzle jump was excessive. The S&W 500 was even worse. Although, because of the muzzle break, the muzzle jump was not all that bad. Again the factor grips were a joke. They did not fill my hand, no palm swell, and they stung my hand severly. The Black Hawk has an unported 7 1/2" barrel and factory grips. The muzzle wipe is rather fierce causing the pistol to pivot in my hand allowing the hammer spur to dig in to my hand a set of hogue grips has stopped the pivoting. Below are some suggestions for solving your problem.
A good set of grips go a long way to controlling the slipage in your hand and reducing some of the felt recoil but to do this the grips must fill your hand, (a generous palm swell). I perfer hogue soft rubber grips. Porting or a muzzle break control the muzzle flop and reduces the felt recoil by as much as 30%. Another trick to reduce the felt recoil is to grip your pistol less tightly. When you grip the pistol tightly you flatten out your skin and the recoil is transmitted to your bones. By increasing the depth of the skin, your skin acts as a shock absorber. The adverse result of this way of gripping the weapon is a higher but consistant bullet impact. Relax and allow your joints, (wrists, elbows and shoulders) to move under the recoil thus speading the recoil over a larger area.
You stated load is a bit hot. Most loads for a 250 grain bullet produce volicities of between 800 and 900 FPS. A heavier bullet pushed even faster will obviously increase recoil. I have owned a 45LC and I loved it. It was fun to shoot and reasonably accurate but it has its limitations. Realisticly it is a 50 yard gun. At that range the bullet has enough inertia and bullet diameter to be an effective killer. Bullets used in large cailber pistol bullets have the bullet coefficiency, (the ability to move throught air), of a brick and therefore slow very quickly. Even if you launch your bullet at 1000 FPS it will quickly slow below the volicity necessary for any kind of bullet expansion.
I submit the following as only suggestions for you to consider. Put the Hogue grips back on, reduce your load, use a lighter grip on the weapon and relax. Only if this does not produce the desired results would I go to the expense of porting.