Really long again, sorry. I do tend to go on about it all, given half an excuse 
Roses are always a great subject for a tattoo, lovely! You've got 3 pretty different styles there but I get the placement you're after. You really don't need heavy or blocky coverage for stretch marks, the tattooing distracts from them entirely even with light / partial coverage in some areas.
So, erm. Yeah.
Tattoo #1 is an a cover-up in progress, probably about 1/2 way done. You can see the old tattoo through the line work - under the butterfly and lily on the left and under the butterfly on the right too. Actually it's showing through the finished colour work as well, which is a shame. The line work looks solid enough (although the picture is showing very small here) but the shading and use of colour in the flowers is a bit of a disaster.
The general style they seem to be aiming for is quite modern - this sort of thing. This, in a related but more abstract style, is bigger but has some lovely movement. It's clearly not flowers but you can see how the flow and shape of the piece work with the body rather than jarring against it. So, despite being bigger it's much 'lighter' on the body than the example.
#2 is a cover-up of an older tattoo too. It's an adequate tattoo, not excellent but pretty much OK. Maybe apprentice level, although they'd usually stick to smaller work and not do cover-ups. Colour saturation could be better. It'd look a lot better if it'd been given room to breath IYSWIM, it's very squished up and blocky. Probably got more to do with the client's choice than the tattooist though, to be fair. I'd not let they person who did it tattoo me though.
Is very much traditional in essence - as in it's a tattoo that looks like a tattoo IYSWIM. this sort of thing. here too. "Traditional" is a pretty broad church in tattooing. The basic style of tattoo is traditional for a lot of good reasons though.
this is maybe between #1 & #2 in terms of style but lighter and with more movement again.
#3 is unfinished and really nasty work. Done-In-A-Filthy-Kitchen-Without-Gloves level. Can it be roses? I think lotus flowers? Water lilies? Maybe even Japanese style peonies actually, looking at the straggly bits that might be intended to be "waves". It's less squished and blocky than the first two though. I just cant make a stab at what sort of style it's after being. Lightly shaded, illustrative stuff can be lovely though. here too. It's a style that should age nicely.
You absolutely don't need to find an example of the exact tattoo you want. Absolutely not. 'Just' a clear idea of the subject(s) and placement and a competent tattooist you feel comfortable with and can trust. Oh yeah, and to be prepared to listen to them and take their advice. Key that.