Dear Sir, I offer my self to be betatester of your new SMP development. Please take in account the next points.
XP minimum cloud layer thickness is 2000ft, then we get a problem with METARs like FEW014 SCT020. I recommend two solutions, one is only create a layer using the maximum coverage of the METAR and the lower base, in this METAR we will convert FEW014 SCT020 to SCT014.
Increase transition time till 30s, if we get no clouds and we get now BKN it could be better to get 30s to make the transition (or just the opposite, from BKN to clear).
Be really careful with bottom cloud level (base) and try to use the dataref (or METAR value) +- 50ft, no more.
Try to mix and be aware of the clouds level, it means that if I get one layer from 4500 AMSL to 6500, another from 7500 to 12500 and the last one from 15000 to 18000 AMSL, try to avoid mixing them and maintain the distance and bottom layer position, the top can be variable (+-200m/600ft) but never reach the base of the next layer.
Kind regards