no, dont use slin needles for oils. actually, i no longer use slin needles at all. mimimun 5/8inch...usually 1 inch for delts and quads. rotate sites for everyday injections ie: glutes, quads, delts... glutes, quads, delts, etc. or, if you're brave, rotate, glutes, quads, delts, bis, tris, calves, etc...... btw, welcome to the board
peace,
ragin'