That being the case:

Donation of Wool - Obtain at 12 (2850xp times 5 = 14,250xp )
Donation of Silk - Obtain at 26 ( 21,600xp times 5 = 108,000xp)
Donation of Mageweave - Obtain at 40 (14,250xp times 5 = 71,250xp)
Donation of Runecloth - Obtain at 50 ( 28,650xp times 5 = 153,250 xp)

Total possible XP for cloth turn-in to all 5 races under RAF is 336,750 xp.