I am in the middle of doing a pair of Remington 1894's for two of my sons to use after I am long gone. So I understand your desire to build what you want and not care about cost or recovery of your investment.

I did a Fox re-chamber years ago. It was a 16 ga. extractor with 30" barrels with chambers that were ruined by two paper shells stored for four or five decades. I am talking about pitting like the craters on the back side of the moon. I chamber sleeved it down to a 20 gauge. It is long range death on doves and pigeons. So much so that I have another donor gun that I am hoping to sleeve to 20 for a second one to pass along.

To your selection list. I rather have extractors than ejectors. Cool only works with others around to see your coolness and I tend to hunt a lot alone or with just one of my sons. And sons know dads are not cool. Not having to work around ejectors inletting give you a lot more flexibility on how you make the fore end. I have been thinking about trying a semi beaver-tail fore end, long and trim with a small Schnabel tip or other shaped end point. Figure to make one and try it, change it as desired and then if it works well use a nice fore end blank to make the real one using it as a pattern.

If you have the time and money I would be thinking in terms of a pair of guns. Perhaps a 28" and a 30" pair with different chokes but the same basic stocks. Kind of a near and far set of guns. Make what you want and enjoy both the process and the product because it is fun to upgrade a gun and see if it meets your goals.