choice of diopter + holder for PT-EP13

I have a 14-42 and a 12-50 for use in my PT-EP13 housing. I'd like to be able to get a bit more magnification without committing to macro for the whole dive (by e.g. putting the 12-50 into macro mode). It seems like a diopter might be a good choice. I'm not really sure what magnification I want. I see Inon has a couple reasonable priced diopters, as does AOI.. This looks like a nice holder, although the olympus plastic thing is much cheaper.

https://uw-pix.com/product/wet-diopter-holder-olympus-housing/

I also noticed Bluewater and Mozaik have house branded +7/+8 diopters. (the latter being interesting because I'm in Canada)

Suggestions or experience reports welcome.

This actually looks nicer (and cheaper) than the uw-pix one, unless I'm confused about what a PPO-EP01 port is.

http://www.divervision.com/howshot-m67-mount-base-120-for-olympus-ppo-ep01-flat-port-RM67-120P.html

You might find my comparisons of the Subsee +5 and +10 diopters useful.  The third set uses the Oly 12-50 lens at 50mm:

https://wetpixel.com/forums/index.php?/topic/56141-comparison-olympus-m43-macro-options/

For what it is worth, a long time ago I tried one of the basic Inon  close-up lenses with an Oly 14-42 lens and found it close to useless

Interesting. I would have expected the Inon ucl-165  to behave similarly to the Subsee +5. OTOH, I guess the 14-42 has quite a bit shorter minimum focusing distance than the 12-50, so you indeed might not see much improvement.