I mean, everything is dialect-specific, and there is a lot of variation between dialects around /æ/ in particular (trap-bath, bad-lad, Mary-marry-merry, and the whole mess of /æ/-raising/tensing - is ban-back an example that's always split?).

But I'd still say it'd be interesting to record your voice and check the actual timings even if you can't consciously hear the length. Assuming you can actually practice running speech while thinking about it, of course.