This is what the royal grammar says about differentiation.
DIFFERENTIA.
Differentia tonum transponit: vt Vná aduerbium, vltimam acuit, ne videatur esse nomen: sic, Eó, aliquó, alió, continuó, seduló, porró, forté, quá, siquá, aliquá, nequá, illó, falsó, citó, feré, plané, & id genus alia: putá pro sicut, poné pro póst, corám, circúm, aliás, palám, ergó coniunctio, sed ergô pro causa, circunflectitur, vt, illius ergô ~Venimus. Haec igitur omnia sicut Graeca acutisona, in fine quidem sententiarum acuuntur, in consequentia verò grauantur.
Sic differentiae causa antepenultima suspenditur in his, Déinde, próinde, périnde, aliquando, sÃquando, húcusque, álonge, délonge, deinceps, dúntaxat, déorsum, quápropter, quÃnimo, enÃmuero, propémodum, Ã¥dmodum, Ã¥ffabre, intereá-loci, nihilóminus, paulóminus, cùm non sunt orationes diuersae, vti sunt, Pube tenus, Crurum tenus, non enim composita sunt, velut Háctenus, quátenus, & eius generis reliqua.
Apart from the secondary sources I listed previously, a great source for quotations is Charles W. Johnson, “The Accentus of the Ancient Latin Grammarians”, Transactions and Proceedings of the American Philological Association, Vol. 35 (1904), pp.65-76. Stable URL http://links.jstor.org/sici?sici=0065-9711(1904)35<65%3ATAOTAL>2.0.CO%3B2-2. But Johnson is not addressing exceptional cases, just the stress-pitch debate about Latin and Greek accenting.