Amazon: Ideas for mounting gauges

[ColoradoAmazon]

I'm looking for ideas where and how to mount gauges. Ideally I'm trying to avoid irreversible holes and cutting things up to install them. I already mounted oil pressure, water temp and volt gauges below the ashtray. I also purchased a tach and an air/fuel gauge I would like to mount.

I obviously wanted one of the Smiths 123 GT tachs but they are not easy to find. I found an Autometer tach in 2-3/8" size that looks somewhat similar but a little larger. I'm debating if I drill a hole in my dash and mount it like the 123 GT. I found a photo of it mounted near the door and that doesn't look bad.

I'm thinking mounting the air/fuel gauge (2-1/16") either on the steering column or near the other gauges under the dash.

I would like to hear ideas and see what other have done as far as location and mounting.

Thanks