The '89 SL100 Clean amp is a great one for the kind of sound you're going for I think. Maybe try playing around with the White Boost also and turn the gain & volume down. '93 MS-30 is underrated for it's "just right" slight tube breakup sound too I think. Just threw together a quick patch with the white boost, SLO Clean, 4x12 Green 25/DYN 7 off axis and liking that alot without any EQs or anything, but a graphic EQ before the amp boosting the mids & highs kinda opens up the gain a bit more for my tastes.

With the MS-30, the 4x10 Super Reverb sounds great, again for my taste and feel. I like to put the True Z on 1Mohm too rather than auto.