One lens to consider is the 120mm f6.3 Osaka (or Congo) wide field. It's a small lens and relatively cheap. I use mine for 5x7 and it covers nicely with very small movements. I find quality is comparable to my other lenses. Having a 120 would be nice between the 90 and 150. But 135's are very common and also cheap. Fairly small. I'd just find them too close to the 150.