No matter how you cut the cookie, the '17 Enfield sporterized is usually heavy and inconvenient. It's costly to do a good job of sporterizing them and the best sporters are usually big big big game rifles. Mine is a .375 H&H and about the right weight for the caliber. They can be turned into .404 Jeffery, and any of the RUM carttridges. They can hold the .300 Weatherby and all the similar cartridges. The .458 Lott and .470 Capstick are "piece of cake" cartridges for this action.....but the weight is justified in these calibers.

With the conditions you've laid out the calibers that might suit you are the .240 Weatherby and the family of .30-06s and that includes the wildcats (6.5-06 and yes even the .338-06)

Any of these cartridges can be housed in actions that are lighter and less costly than the '17 Enfield conversion.

Staying within your limitations, I'd pick the .280 Remington.

However, I'd ask you to rethink the question to yourself.