hi Mel
meant to say that these Bristol coloured drinking glasses weren't apparently intended for wine, but were made for drinking port - and
as to the bowl shape, it seems to be that if there is any flaring to the bowl then it's trumpet, but if the sides are straight then it's conical.
The colour is not a major factor - these things came in a variety of shades, from pale to very dark, so it doesn't help when dating.
For period, the foot should be generous in diameter when compared with size of the rim - and a possible indication of a Georgian/Regency bowl is that small raised cushion (sometimes with a central dimple) found at the bottom of the bowl - as opposed to a plain curved profile of later bowls.
Feet should have plenty of striations and tool marks, and if early C19 is likely to have an edge profile that curves downward to meet a flat foot.
Don't think you want to see a symmetrically round edge to the foot. I could be wrong, but would prefer to see a depression under the foot rather than a snapped scar.
I've six or seven of these things, but must admit to not really being sure about them - green was a much copied colour, especially in drinking glasses, well into the C20 - and I dare say are still being made. There's hardly an antiques centre anywhere that doesn't have a few knopped, conical shaped, Bristol green 'Georgian' glasses - allegedly - on show.

May well be wrong, but regret to say I'm still of the opinion that your glass appears too slim for period.
Neil might also have some ideas on this - believe he collects this period.