If you can do the work yourself and the rest of the vehicle is sound, then HG on a 20 year old Foz makes sense I suppose. Although at 190k miles, the next problems will occur soon. Does it use oil? Have piston slap? Transmission sound, maintained with some fluid exchanges or flushes?
The cost to have a shop "fix" your HG is likely money thrown away. If you doing it yourself out of principle or cause you have time and knowledge (and less money) then go for it.
I extensively looked over HG options for my NA 2005. Six Star are very well regarded. So are the Turbo MLS Subaru gaskets. And, I think the lastest Felpro MLS are also OK.
But the caveat to all these recommendations is what the BLOCK looks like. If the heads are off, you need to have them looked at by a good machine shop that does heads. I think every metropolitan city has one or more. Find it. But the block gets overlooked. If you look at Subaru specs carefully, the block needs to be true to like .0015. Well the block is made of aluminum! And the last guys that did the last HG repair might have butchered the block.
Your story, with the latest HG lasting at least 55k miles, argues that the block is NOT toast. But make sure you check with a quality straight edge nonetheless.
Finally, re bolts. They are not that expensive. Get some OEM Subaru ones, and find the proper torque sequence. They ARE re-usable. They are NOT torque to stretch as some posts will maintain. I think if you can say positively that your head bolts are Subaru original, then I'd re-use them. Otherwise, I'd replace with subaru OEM. Read too many stories about the bolts from china....