This is your adhesive for glass
BAL Mosaic-Fix
Tile Adhesive
A bright white, non-slip, water and frost-resistant, cementitious wall and floor
tile adhesive specially formulated for fixing mosaic tiles including glass mosaics. It is also suitable for fixing ceramic wall and floor tiles, metal or
glass tiles, marble, terrazzo, and natural stone in interior and exterior locations. Suitable for use in swimming pools. Can be used on most surfaces including MDF (in internal dry areas).
and grout should be polymer modified to stick to the sides
BAL Superflex Wall Grout
A brilliant white, water & frost resistant cementitious wall
tile grout with built-in admixture to give increased flexibility and high bond strength. Suitable for grouting porcelain, marble, natural stone,
glass and ceramic mosaics, glazed and fully vitrified tiles. BS EN 13888 CG2 Grout.
As regards cutting use fine blade wet saw,if glass face spelches then cut from rear.....always wear protective eyewear....Gaz