you better whip one up .
it will help all you mentioned but its not ( a must have) to build good Damascus but it is ( a must have ) to build great Damascus .
No im just kidding its like most tools it will make life easer but to say every one needs one would be misleading ; A press is not for every one some do great with the tools you mention but when the pain and the need for a better way is telling you need to do something different ,they are to me the ticket .
so no one misunderstands this is a cheep and underhanded way to talk presses what can I say im shameless
al kidding aside hope you find some thing to help with your pain I know what strained arms are have you looked to better hammers that are designed to help with this problem also get a brace that will keep the muscle from blowing up they help most of all also be sure that you worm up the arm before starting you have to remember your using muscles that you have not used before , go to a smaller hammer till you get past the pain if you push it will cause damage that you might not get past , .
what ever you do be sure to stop at the least pain and rest a few it could save your arm hope this helps
but im still shameless ant i ,sham ,sham,sham on me
o ya i almost forgot if the wife is reading this then i would say
HECK YA YOU NEED ONE AND YOU NEED TO START IT TOMORROW YOUR ARM DEPENDS ON IT ,