Belaying With Glacier Harness

I have a glacier-specific harness (Grivel Mistral) that has a horizontal loop, which serves as both the tie-in point and belay loop. Because of this whenever I belay a partner I have to either put up with a sideways oriented belay device, or use an additional carabiner to turn the belay device 90*.

Could I simply attach my belay device to the figure 8 loop that I'm tied into? I don't see why this would be a problem but it seems unnatural.

That’s what they teach in the UK. 

The technical notice is a good place to start. It looks like they suggest using a clepsydra carabiner or similar.

https://cdn.shopify.com/s/files/1/0030/4044/4451/files/IS_harness_HAMIS_Mistral_14A.pdf?v=1593790614

Great thank you both

If you plan on belaying off your tie-in loop, it's better practice to tie in with a ring bend (aka water knot/retraced overhand/"bro knot"). Better resistance to ring loading than a retraced figure 8. Also possible to tie in with a bowline, though some variants are more resistant to ring loading than others.

Ring loading a figure 8 tie in essentially turns it into a flat figure 8 in terms of where the forces involved, and the flat figure 8 is known to capsize when ring loaded.

One thing to think of when using those minimalist harnesses and how they are attached to possible falling climbers is the cajones. Maybe try it out on a little test fall to see how they get involved lest suffer grave pain later.

I would imagine you could basket hitch a 60cm sling , or halve it, and then basket it (in order to shorten this makeshift belay loop) to your belay biner. If that makes any sense. 

https://www.karstsports.com/kong-ovalone-dna-carbon-steel-twistlock-ce-en-362-b/?utm_source=google&utm_medium=cpc&adpos=&scid=scplpK055787&sc_intid=K055787&gclid=Cj0KCQjwmICoBhDxARIsABXkXlJqe5MAwrcGBQr5cl-7Orie6H-ZSJRoxtkFxABk06ZQ_o66sFZHgu4aAhnhEALw_wcB

Would this work? Carabiner that’s twisted 90 degrees.

I have the BD Alpine Bod harness. These minimalist glacier harnesses are certainly not made for comfort and convenience in situations calling for "pitching it out", but I have used mine for that on several occasions. I use a large HMS carabiner for belaying off this harness. This provides a larger opening for clipping the crotch and waist loop and makes it easier to achieve some amount of twisting of the biner to better orient the belay device. I've found this was sufficient for the times I used the harness.

I would simply belay a little skewed, it's really not that bad, no difference to a centre harness. 

I wouldn't belay off your figure 8, not out of safety issues(normal figure 8's are absolutely fine) but simply out of ease of use, your belay device would be even higher than it already will be from the high tie in loop. If you are having to do much belaying you should get a different harness, these harnesses are really only made for glaviel travel and low angle rappelling. 

Having spent a summer teaching kids to belay with similar harnesses, I would say to belay with the belay device sideways. Have the brake strand on your dominant side and the climber strand on the other. I'd also load the rope in the top slot of the belay device as you would normally load it in the dominant-hand side. It does take a bit of getting used to but it works just fine.

Until the mid80s or so, we all belayed side to side if we had a atc type or Sticht plate for belaying.  For right handers, the left hand feeds the leader pulling first out in a modest diagonal, them pushing to straight up.  The right hand feeds levelly into the device.  The important thing is not to get at all close to the device.  To hold a large fall, you want to have enough slack to whip the brake hand behind your upper thigh.  This gives additional braking power at the device, and friction around you leg.  Or at least a lot of us did it that way.