Back of a Fag Packet Calculation but if you did the following using the offer

All BA Flight Numbered Holiday costing c£4k (using my last as reference)

GLA-LHR-BOS-LAX-BOS-JFK-LHR-GLA all in J

Hotels in LA and BOS

You would get 4000 NTP's for the holiday + 2125 NTPS using the bonus offer.

This would be 6215 NTPs.

Then using the offer 3 x GLA - LON returns in J for c£200 per flight would yield c130 NTPs so 390 NTPs then a further 1050 Bonus NTP's would give you 7655 NTPS.

So Silver for about £4,600.

I estimate the Y Road Warrior spending £60 a flight would be about £3k to get their 50. Which is probably no change for them anyway.