G'day Paz,
go the 6x47mm lapua. here's why...............
1. mine shot 2 x 5 shot groups today in crap weather at little river Vic that went <0.6" at 150yds.
2. at 500m today 2 shots & both hit within 1 inch.
3. 1 pass with forster 6x47 FLS with off the shelf 6.5x47 lap brass and you're ready to reload (couldn't get any easier to source brass and dies regardless of cost)
4. small rifle primer (use a magnum) AND MORE IMPORTANTLY as SMALL flash hole to reduce pressure in primer pocket (reduces blown primers = increased chamber pressure and higher MV)
5. IT IS WHAT THE 6-250 SHOULD BE and would make a GREAT 22x47 (read: 22-250 AI) for varminting as if the 6x47 isn't a great round anyway................70gn Sierra MK fireforming loads went less than 0.4moa for 10 shots @ 100yds.

Shoots like a 6ppc
6. NEVER compromise on a custom rifle project as you will nearly always regret it.
It simply does NOT get any easier to form a wildcat that this. Great value for $$$$.
Best part is the difference between the 6xc and 6x47 is stuff all ballistically.
I'm biased if you cant already tell
Cheerio Ned