Here's the third recommendation of counting in base-52:
0, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, a0, aa, ab, ac, ad, ae, af, ag, ah, ai, aj, ak, al, am, an, ao, ap, aq, ar, as, at, au, av, aw, ax, ay, az, aA, aB, aC, aD, aE, aF, aG, aH, aI, aJ, aK, aL, aM, aN, aO, aP, aQ, aR, aS, aT, aU, aV, aW, aX, aY, b0, ba, ...
(The zero's do need a font that puts a diagonal line through them. The zero's flag the group counts and the zero's allow for a sensible addition operation.)
Then
(52 + 48) base-10 = (a0 + V) base-52 = aV base-52
And for instance
(54 + 25) base-10 = (52 + 27) base-10 = (a0 + A) base-52 = aA base-52 .