Update. . . Huge thanks to Chris
@Satanfriendly for kindly loaning me 2 razors and an extra head to try out during my 2 week holiday. From my opening post in this topic, you will know that I was keen to try out both an open comb and a more efficient closed razor. Well thankfully I managed to try out a more efficient razor (iKon B1 solid bar) and TWO open combs (ATT M2 and iKon B1 Deluxe), and experience the satisfying heft of stainless handles for the first time to boot. Also passed my way were 2 Polsilver Lodz (brown box) blades, which I had read lots about and was looking forward to trying. That I managed to wield these tools in an en suite bathroom with crap lighting (no natural light coming in other than a dinner plate sized skylight on the ceiling and no light directly over the mirror) without a bloodfest ensuing was a miracle in itself, but I got some great shaves. . . . .
2 weeks, same brush (Muhle STF), cream (Truefitt & Hill Ultimate Comfort) and blades (Polsilver Lodz), 2 days growth at each shave. . . So, my very first open comb shave. iKon B1 Deluxe on ATT Colossus handle, a relatively mild OC I am led to believe. . . First thoughts were that the handle is huge and heavy, but I really like it, resting my little finger on the handle end, letting the weight do the work and trying to use lightest pressure I could. Despite getting 2 nicks (I rarely nick myself, damage doesn't normally extend beyond a few weepers), I really enjoyed the OC experience. I think one of those nicks was inadvertently catching a bump, no idea how the other one happened. I'd read that open combs are good in that more lather passes through the teeth to the blade, instead of a solid bar pushing it around the face & clogging the head up. I certainly found this to be true, and whilst to date I wasn't one to analyse stubble in the lather in the sink, I couldn't help but notice that there was more of it in there than after a WTG pass with the DE89. There were also longer, slightly curved hairs in there as well as the run of the mill stubble I'd expect from 2 days' growth. So I figured that if its removing hairs that a mild closed comb isn't, that can only be a good thing. Noticeably better results after the XTG pass too. I was wary about going ATG right off the bat with an OC, so I just did another XTG pass in the other direction. Same shave repeated 2 days later minus the nicks. Third shave I was brave enough to try ATG at the end, definitely the easiest ATG pass I've done, most likely due to more hair having been taken out by the first 2 passes than what I've been used to. Just a few weepers, but no nicks and a great, smooth result. Really liking this razor. Head feels pure quality and locating guides make aligning the blade effortless.
Next up, ATT M2 open comb on Kronos handle. Excellent handle again, couldn't pick between this and the longer Colossus really. As with the iKon, I did 2 shaves WTG, XTG, and XTG other way, and on the third I went WTG, XTG & ATG. For some reason I really wanted to love the ATT, but the shave and results of the iKon were simply better for me. The ATT felt a little rougher during the shave, perhaps the teeth are a bit sharper, and I got more irritation post shave, and a few more weepers. A shallower angle helped a little but overall the iKon gave better results.
Finally, onto the vicious monster that is the iKon B1 solid bar plate. . . I had been warned, so tried to take it steady, but this razor takes no prisoners! Saved up 3 days' growth for this one (normally 2 is my max), WTG & XTG passes were extremely efficient. Why I didn't stop there is anybody's guess, but I did a full ATG pass and was punished with about 20 weepers. Hands down the most uncomfortable ATG pass ever and I realised afterwards that I was stupid for not stopping said pass in its tracks earlier on! Had another shave with this minus the ATG and though it was pretty close, I used the DE89 for touch-ups as I was too scared to go back over areas again with the iKon SB.
So to summarise: Open combs have been an eye-opener for me. Before I'd even returned the loan razors, I'd ordered a used iKon B1 Deluxe OC from a TSR member. I am getting a more efficient shave resulting in less irritation, which is exactly what I was hoping to find. I may still try a slant and an SE some day, but for now I'll stick with this and see which of my blades perform best for me in it. Polsilver Lodz blade very good too, will probably order some when I next order blades. Thanks for your input everyone.