With options in the cabinet for 243, 6.5, and 308, I've read this thread with interest.
Completely agree with the points re Hilar zone shooting - this or neck should be the standards for the BDS etc. Prioritising meat retention over the certainty of killing and finding a deer is nuts, particularly with current game dealer prices.
This approach makes bullet selection less of a factor, but my takes.
243 - hunting, Hornady 95g Super Performance SST, devastating, highly accurate, shot sub-MOA at 900y at Bisley. Use for static shooting of fallow / roe / muntjac from high seats.
243 - range, 105g scenar
308 - hunting, have used Federal Powershok 150g very consistently for all deer, cheap and effective, chrono has shown single figure SD values at points. Recently started using a handload of ELD-X 178g loaded to 2600fps - the BC figures are hard to argue with but have not (yet) taken any body shots.
308 - range, don't generally shoot that seriously but have good results with the (very cheap) GGG 168g which is a Sierra HPBT at 2650
6.5 - range, Hornady ELD-M 147g. Have shot this consistently to 1300m.
All of the above based on very limited time to load, so reliance mainly on factory ammo. What is interesting - for every calibre Nathan Foster recommends using the heaviest A-Max / ELD-M head available. This makes a lot of sense ballistically, and the light jackets should give flexibility at ranges where velocity is >=1800fps. This is where the 6.5 gets really interesting, as it has the BC values to be a great range rifle, and is supersonic c.300m further than 308 with conservative loads, with a similar difference in the magic 1800fps barrier. Most of this is about having fun with numbers, but the flexibility of the 6.5CM, and accuracy with easily available factory ammo makes it a real swiss army knife.